diff --git a/.clang-tidy b/.clang-tidy
index 03f7f39d2..229e2e69a 100644
--- a/.clang-tidy
+++ b/.clang-tidy
@@ -49,6 +49,8 @@ Checks: >
     -misc-misplaced-const,
     -misc-definitions-in-headers,
     -misc-unused-parameters,
+    modernize-concat-nested-namespaces,
+    modernize-use-using,
     performance-*,
     -performance-noexcept-move-constructor,
     -performance-no-int-to-ptr,
diff --git a/include/contractor/contract_excludable_graph.hpp b/include/contractor/contract_excludable_graph.hpp
index 2f49e68eb..05567f287 100644
--- a/include/contractor/contract_excludable_graph.hpp
+++ b/include/contractor/contract_excludable_graph.hpp
@@ -7,9 +7,7 @@
 #include "contractor/graph_contractor_adaptors.hpp"
 #include "contractor/query_graph.hpp"
 
-namespace osrm
-{
-namespace contractor
+namespace osrm::contractor
 {
 
 using GraphAndFilter = std::tuple<QueryGraph, std::vector<std::vector<bool>>>;
@@ -94,7 +92,6 @@ inline auto contractExcludableGraph(ContractorGraph contractor_graph_,
     return GraphAndFilter{QueryGraph{num_nodes, edge_container.edges},
                           edge_container.MakeEdgeFilters()};
 }
-} // namespace contractor
 } // namespace osrm
 
 #endif
diff --git a/include/contractor/contracted_edge_container.hpp b/include/contractor/contracted_edge_container.hpp
index db3ae5cc9..89affa65a 100644
--- a/include/contractor/contracted_edge_container.hpp
+++ b/include/contractor/contracted_edge_container.hpp
@@ -14,9 +14,7 @@
 #include <numeric>
 #include <vector>
 
-namespace osrm
-{
-namespace contractor
+namespace osrm::contractor
 {
 
 struct ContractedEdgeContainer
@@ -164,7 +162,6 @@ struct ContractedEdgeContainer
     std::vector<MergedFlags> flags;
     std::vector<QueryEdge> edges;
 };
-} // namespace contractor
 } // namespace osrm
 
 #endif
diff --git a/include/contractor/contracted_metric.hpp b/include/contractor/contracted_metric.hpp
index c795a139a..184e6aae2 100644
--- a/include/contractor/contracted_metric.hpp
+++ b/include/contractor/contracted_metric.hpp
@@ -3,9 +3,7 @@
 
 #include "contractor/query_graph.hpp"
 
-namespace osrm
-{
-namespace contractor
+namespace osrm::contractor
 {
 
 namespace detail
@@ -19,7 +17,6 @@ template <storage::Ownership Ownership> struct ContractedMetric
 
 using ContractedMetric = detail::ContractedMetric<storage::Ownership::Container>;
 using ContractedMetricView = detail::ContractedMetric<storage::Ownership::View>;
-} // namespace contractor
 } // namespace osrm
 
 #endif
diff --git a/include/contractor/contractor.hpp b/include/contractor/contractor.hpp
index a0335d8ea..5db562e30 100644
--- a/include/contractor/contractor.hpp
+++ b/include/contractor/contractor.hpp
@@ -30,9 +30,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include "contractor/contractor_config.hpp"
 
-namespace osrm
-{
-namespace contractor
+namespace osrm::contractor
 {
 
 /// Base class of osrm-contract
@@ -49,7 +47,6 @@ class Contractor
   private:
     ContractorConfig config;
 };
-} // namespace contractor
 } // namespace osrm
 
 #endif // PROCESSING_CHAIN_HPP
diff --git a/include/contractor/contractor_config.hpp b/include/contractor/contractor_config.hpp
index 18e8ae222..164065cb0 100644
--- a/include/contractor/contractor_config.hpp
+++ b/include/contractor/contractor_config.hpp
@@ -35,9 +35,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include <string>
 
-namespace osrm
-{
-namespace contractor
+namespace osrm::contractor
 {
 
 struct ContractorConfig final : storage::IOConfig
@@ -71,7 +69,6 @@ struct ContractorConfig final : storage::IOConfig
     //(e.g. 0.8 contracts 80 percent of the hierarchy, leaving a core of 20%)
     double core_factor = 1.0;
 };
-} // namespace contractor
 } // namespace osrm
 
 #endif // EXTRACTOR_OPTIONS_HPP
diff --git a/include/contractor/contractor_graph.hpp b/include/contractor/contractor_graph.hpp
index e8cef068a..13d44985f 100644
--- a/include/contractor/contractor_graph.hpp
+++ b/include/contractor/contractor_graph.hpp
@@ -4,9 +4,7 @@
 #include "util/dynamic_graph.hpp"
 #include <algorithm>
 
-namespace osrm
-{
-namespace contractor
+namespace osrm::contractor
 {
 
 struct ContractorEdgeData
@@ -42,7 +40,6 @@ struct ContractorEdgeData
 using ContractorGraph = util::DynamicGraph<ContractorEdgeData>;
 using ContractorEdge = ContractorGraph::InputEdge;
 
-} // namespace contractor
 } // namespace osrm
 
 #endif // OSRM_CONTRACTOR_CONTRACTOR_GRAPH_HPP_
diff --git a/include/contractor/contractor_heap.hpp b/include/contractor/contractor_heap.hpp
index 7f505bb8a..79fce9df5 100644
--- a/include/contractor/contractor_heap.hpp
+++ b/include/contractor/contractor_heap.hpp
@@ -5,9 +5,7 @@
 #include "util/typedefs.hpp"
 #include "util/xor_fast_hash_storage.hpp"
 
-namespace osrm
-{
-namespace contractor
+namespace osrm::contractor
 {
 struct ContractorHeapData
 {
@@ -24,7 +22,6 @@ using ContractorHeap = util::QueryHeap<NodeID,
                                        ContractorHeapData,
                                        util::XORFastHashStorage<NodeID, NodeID>>;
 
-} // namespace contractor
 } // namespace osrm
 
 #endif // OSRM_CONTRACTOR_CONTRACTOR_HEAP_HPP_
diff --git a/include/contractor/contractor_search.hpp b/include/contractor/contractor_search.hpp
index 246228980..ebc0b40b9 100644
--- a/include/contractor/contractor_search.hpp
+++ b/include/contractor/contractor_search.hpp
@@ -8,9 +8,7 @@
 
 #include <cstddef>
 
-namespace osrm
-{
-namespace contractor
+namespace osrm::contractor
 {
 
 void search(ContractorHeap &heap,
@@ -20,7 +18,6 @@ void search(ContractorHeap &heap,
             const EdgeWeight weight_limit,
             const NodeID forbidden_node);
 
-} // namespace contractor
 } // namespace osrm
 
 #endif // OSRM_CONTRACTOR_DIJKSTRA_HPP
diff --git a/include/contractor/crc32_processor.hpp b/include/contractor/crc32_processor.hpp
index a441ae576..c909731ba 100644
--- a/include/contractor/crc32_processor.hpp
+++ b/include/contractor/crc32_processor.hpp
@@ -9,9 +9,7 @@
 
 #include <iterator>
 
-namespace osrm
-{
-namespace contractor
+namespace osrm::contractor
 {
 
 class IteratorbasedCRC32
@@ -125,7 +123,6 @@ struct RangebasedCRC32
   private:
     IteratorbasedCRC32 crc32;
 };
-} // namespace contractor
 } // namespace osrm
 
 #endif /* ITERATOR_BASED_CRC32_H */
diff --git a/include/contractor/files.hpp b/include/contractor/files.hpp
index 39ffa5b54..6c747b6cf 100644
--- a/include/contractor/files.hpp
+++ b/include/contractor/files.hpp
@@ -5,11 +5,7 @@
 
 #include <unordered_map>
 
-namespace osrm
-{
-namespace contractor
-{
-namespace files
+namespace osrm::contractor::files
 {
 // reads .osrm.hsgr file
 template <typename ContractedMetricT>
@@ -52,8 +48,6 @@ inline void writeGraph(const boost::filesystem::path &path,
         serialization::write(writer, "/ch/metrics/" + pair.first, pair.second);
     }
 }
-} // namespace files
-} // namespace contractor
 } // namespace osrm
 
 #endif
diff --git a/include/contractor/graph_contractor.hpp b/include/contractor/graph_contractor.hpp
index a6a3891c2..2df62c795 100644
--- a/include/contractor/graph_contractor.hpp
+++ b/include/contractor/graph_contractor.hpp
@@ -8,9 +8,7 @@
 #include <tuple>
 #include <vector>
 
-namespace osrm
-{
-namespace contractor
+namespace osrm::contractor
 {
 
 std::vector<bool> contractGraph(ContractorGraph &graph,
@@ -37,7 +35,6 @@ inline auto contractGraph(ContractorGraph &graph,
         graph, {}, std::move(node_is_contractable), std::move(node_weights), core_factor);
 }
 
-} // namespace contractor
 } // namespace osrm
 
 #endif // OSRM_CONTRACTOR_GRAPH_CONTRACTOR_HPP
diff --git a/include/contractor/graph_contractor_adaptors.hpp b/include/contractor/graph_contractor_adaptors.hpp
index cfd447efb..a622b9048 100644
--- a/include/contractor/graph_contractor_adaptors.hpp
+++ b/include/contractor/graph_contractor_adaptors.hpp
@@ -10,9 +10,7 @@
 
 #include <vector>
 
-namespace osrm
-{
-namespace contractor
+namespace osrm::contractor
 {
 
 // Make sure to move in the input edge list!
@@ -177,7 +175,6 @@ template <class Edge, typename GraphT> inline std::vector<Edge> toEdges(GraphT g
     return edges;
 }
 
-} // namespace contractor
 } // namespace osrm
 
 #endif // OSRM_CONTRACTOR_GRAPH_CONTRACTION_ADAPTORS_HPP_
diff --git a/include/contractor/query_edge.hpp b/include/contractor/query_edge.hpp
index 08f163044..f8281ac0e 100644
--- a/include/contractor/query_edge.hpp
+++ b/include/contractor/query_edge.hpp
@@ -5,9 +5,7 @@
 
 #include <tuple>
 
-namespace osrm
-{
-namespace contractor
+namespace osrm::contractor
 {
 
 struct QueryEdge
@@ -77,7 +75,6 @@ struct QueryEdge
                 data.distance == right.data.distance);
     }
 };
-} // namespace contractor
 } // namespace osrm
 
 #endif // QUERYEDGE_HPP
diff --git a/include/contractor/query_graph.hpp b/include/contractor/query_graph.hpp
index c0c4b6cf5..ad7844435 100644
--- a/include/contractor/query_graph.hpp
+++ b/include/contractor/query_graph.hpp
@@ -6,9 +6,7 @@
 #include "util/static_graph.hpp"
 #include "util/typedefs.hpp"
 
-namespace osrm
-{
-namespace contractor
+namespace osrm::contractor
 {
 
 namespace detail
@@ -19,7 +17,6 @@ using QueryGraph = util::StaticGraph<typename QueryEdge::EdgeData, Ownership>;
 
 using QueryGraph = detail::QueryGraph<storage::Ownership::Container>;
 using QueryGraphView = detail::QueryGraph<storage::Ownership::View>;
-} // namespace contractor
 } // namespace osrm
 
 #endif // QUERYEDGE_HPP
diff --git a/include/contractor/serialization.hpp b/include/contractor/serialization.hpp
index 693216d6a..da9ec8bdb 100644
--- a/include/contractor/serialization.hpp
+++ b/include/contractor/serialization.hpp
@@ -8,11 +8,7 @@
 #include "storage/serialization.hpp"
 #include "storage/tar.hpp"
 
-namespace osrm
-{
-namespace contractor
-{
-namespace serialization
+namespace osrm::contractor::serialization
 {
 
 template <storage::Ownership Ownership>
@@ -46,8 +42,6 @@ void read(storage::tar::FileReader &reader,
                                      metric.edge_filter[index]);
     }
 }
-} // namespace serialization
-} // namespace contractor
 } // namespace osrm
 
 #endif
diff --git a/include/customizer/cell_customizer.hpp b/include/customizer/cell_customizer.hpp
index 8a104e2e0..5cb924c89 100644
--- a/include/customizer/cell_customizer.hpp
+++ b/include/customizer/cell_customizer.hpp
@@ -10,9 +10,7 @@
 
 #include <unordered_set>
 
-namespace osrm
-{
-namespace customizer
+namespace osrm::customizer
 {
 
 class CellCustomizer
@@ -235,7 +233,6 @@ class CellCustomizer
 
     const partitioner::MultiLevelPartition &partition;
 };
-} // namespace customizer
 } // namespace osrm
 
 #endif // OSRM_CELLS_CUSTOMIZER_HPP
diff --git a/include/customizer/cell_metric.hpp b/include/customizer/cell_metric.hpp
index a522facc3..2adf713fb 100644
--- a/include/customizer/cell_metric.hpp
+++ b/include/customizer/cell_metric.hpp
@@ -7,9 +7,7 @@
 #include "util/typedefs.hpp"
 #include "util/vector_view.hpp"
 
-namespace osrm
-{
-namespace customizer
+namespace osrm::customizer
 {
 namespace detail
 {
@@ -26,7 +24,6 @@ template <storage::Ownership Ownership> struct CellMetricImpl
 
 using CellMetric = detail::CellMetricImpl<storage::Ownership::Container>;
 using CellMetricView = detail::CellMetricImpl<storage::Ownership::View>;
-} // namespace customizer
 } // namespace osrm
 
 #endif
diff --git a/include/customizer/customizer.hpp b/include/customizer/customizer.hpp
index a7716cf1b..40d2583f8 100644
--- a/include/customizer/customizer.hpp
+++ b/include/customizer/customizer.hpp
@@ -3,9 +3,7 @@
 
 #include "customizer/customizer_config.hpp"
 
-namespace osrm
-{
-namespace customizer
+namespace osrm::customizer
 {
 
 class Customizer
@@ -14,7 +12,6 @@ class Customizer
     int Run(const CustomizationConfig &config);
 };
 
-} // namespace customizer
 } // namespace osrm
 
 #endif // OSRM_CUSTOMIZE_CUSTOMIZER_HPP
diff --git a/include/customizer/customizer_config.hpp b/include/customizer/customizer_config.hpp
index 4df629de5..ca5258fb2 100644
--- a/include/customizer/customizer_config.hpp
+++ b/include/customizer/customizer_config.hpp
@@ -9,9 +9,7 @@
 #include "storage/io_config.hpp"
 #include "updater/updater_config.hpp"
 
-namespace osrm
-{
-namespace customizer
+namespace osrm::customizer
 {
 
 struct CustomizationConfig final : storage::IOConfig
@@ -39,7 +37,6 @@ struct CustomizationConfig final : storage::IOConfig
 
     updater::UpdaterConfig updater_config;
 };
-} // namespace customizer
 } // namespace osrm
 
 #endif // OSRM_CUSTOMIZE_CUSTOMIZER_CONFIG_HPP
diff --git a/include/customizer/edge_based_graph.hpp b/include/customizer/edge_based_graph.hpp
index b90f464a7..2f5a552b2 100644
--- a/include/customizer/edge_based_graph.hpp
+++ b/include/customizer/edge_based_graph.hpp
@@ -11,9 +11,7 @@
 
 #include <boost/filesystem/path.hpp>
 
-namespace osrm
-{
-namespace customizer
+namespace osrm::customizer
 {
 
 struct EdgeBasedGraphEdgeData
@@ -126,7 +124,6 @@ using MultiLevelEdgeBasedGraph =
     MultiLevelGraph<EdgeBasedGraphEdgeData, storage::Ownership::Container>;
 using MultiLevelEdgeBasedGraphView =
     MultiLevelGraph<EdgeBasedGraphEdgeData, storage::Ownership::View>;
-} // namespace customizer
 } // namespace osrm
 
 #endif
diff --git a/include/customizer/files.hpp b/include/customizer/files.hpp
index 335b77a30..287ca5063 100644
--- a/include/customizer/files.hpp
+++ b/include/customizer/files.hpp
@@ -9,11 +9,7 @@
 
 #include <unordered_map>
 
-namespace osrm
-{
-namespace customizer
-{
-namespace files
+namespace osrm::customizer::files
 {
 
 // reads .osrm.cell_metrics file
@@ -106,8 +102,6 @@ inline void writeGraph(const boost::filesystem::path &path,
     writer.WriteFrom("/mld/connectivity_checksum", connectivity_checksum);
     serialization::write(writer, "/mld/multilevelgraph", graph);
 }
-} // namespace files
-} // namespace customizer
 } // namespace osrm
 
 #endif
diff --git a/include/customizer/serialization.hpp b/include/customizer/serialization.hpp
index c242f8ba3..158d37a39 100644
--- a/include/customizer/serialization.hpp
+++ b/include/customizer/serialization.hpp
@@ -9,11 +9,7 @@
 #include "storage/shared_memory_ownership.hpp"
 #include "storage/tar.hpp"
 
-namespace osrm
-{
-namespace customizer
-{
-namespace serialization
+namespace osrm::customizer::serialization
 {
 
 template <storage::Ownership Ownership>
@@ -65,8 +61,6 @@ inline void write(storage::tar::FileWriter &writer,
     storage::serialization::write(writer, name + "/is_backward_edge", graph.is_backward_edge);
     storage::serialization::write(writer, name + "/node_to_edge_offset", graph.node_to_edge_offset);
 }
-} // namespace serialization
-} // namespace customizer
 } // namespace osrm
 
 #endif
diff --git a/include/engine/algorithm.hpp b/include/engine/algorithm.hpp
index 1d65cac04..eca88b21c 100644
--- a/include/engine/algorithm.hpp
+++ b/include/engine/algorithm.hpp
@@ -3,11 +3,7 @@
 
 #include <type_traits>
 
-namespace osrm
-{
-namespace engine
-{
-namespace routing_algorithms
+namespace osrm::engine::routing_algorithms
 {
 
 // Contraction Hiearchy
@@ -111,8 +107,6 @@ template <> struct HasGetTileTurns<mld::Algorithm> final : std::true_type
 template <> struct HasExcludeFlags<mld::Algorithm> final : std::true_type
 {
 };
-} // namespace routing_algorithms
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/api/base_api.hpp b/include/engine/api/base_api.hpp
index 0cd066d0f..a1ce063f1 100644
--- a/include/engine/api/base_api.hpp
+++ b/include/engine/api/base_api.hpp
@@ -18,11 +18,7 @@
 #include <memory>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace api
+namespace osrm::engine::api
 {
 
 static const constexpr char *INTERSECTION_DELIMITER = " / ";
@@ -170,8 +166,6 @@ class BaseAPI
     const BaseParameters &parameters;
 };
 
-} // namespace api
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/api/base_parameters.hpp b/include/engine/api/base_parameters.hpp
index d5bb71a53..7e243dc98 100644
--- a/include/engine/api/base_parameters.hpp
+++ b/include/engine/api/base_parameters.hpp
@@ -38,11 +38,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <algorithm>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace api
+namespace osrm::engine::api
 {
 
 /**
@@ -124,8 +120,6 @@ struct BaseParameters
                            });
     }
 };
-} // namespace api
-} // namespace engine
 } // namespace osrm
 
 #endif // ROUTE_PARAMETERS_HPP
diff --git a/include/engine/api/base_result.hpp b/include/engine/api/base_result.hpp
index 5dd63e7a9..eae87550a 100644
--- a/include/engine/api/base_result.hpp
+++ b/include/engine/api/base_result.hpp
@@ -8,16 +8,10 @@
 
 #include "util/json_container.hpp"
 
-namespace osrm
-{
-namespace engine
-{
-namespace api
+namespace osrm::engine::api
 {
 using ResultT =
     mapbox::util::variant<util::json::Object, std::string, flatbuffers::FlatBufferBuilder>;
-} // namespace api
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/api/flatbuffers/fbresult_generated.h b/include/engine/api/flatbuffers/fbresult_generated.h
index 05211bec6..ec5690022 100644
--- a/include/engine/api/flatbuffers/fbresult_generated.h
+++ b/include/engine/api/flatbuffers/fbresult_generated.h
@@ -6,10 +6,7 @@
 
 #include "flatbuffers/flatbuffers.h"
 
-namespace osrm {
-namespace engine {
-namespace api {
-namespace fbresult {
+namespace osrm::engine::api::fbresult {
 
 struct Position;
 
@@ -2431,9 +2428,6 @@ inline std::unique_ptr<osrm::engine::api::fbresult::FBResultT> UnPackSizePrefixe
   return std::unique_ptr<osrm::engine::api::fbresult::FBResultT>(GetSizePrefixedFBResult(buf)->UnPack(res));
 }
 
-}  // namespace fbresult
-}  // namespace api
-}  // namespace engine
 }  // namespace osrm
 
 #endif  // FLATBUFFERS_GENERATED_FBRESULT_OSRM_ENGINE_API_FBRESULT_H_
diff --git a/include/engine/api/json_factory.hpp b/include/engine/api/json_factory.hpp
index f92dba16a..3e3c98005 100644
--- a/include/engine/api/json_factory.hpp
+++ b/include/engine/api/json_factory.hpp
@@ -19,16 +19,12 @@
 #include <string>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
+namespace osrm::engine
 {
 
 struct Hint;
 
-namespace api
-{
-namespace json
+namespace api::json
 {
 namespace detail
 {
@@ -112,9 +108,7 @@ util::json::Object makeRouteLeg(guidance::RouteLeg leg, util::json::Array steps)
 util::json::Array makeRouteLegs(std::vector<guidance::RouteLeg> legs,
                                 std::vector<util::json::Value> step_geometries,
                                 std::vector<util::json::Object> annotations);
-} // namespace json
 } // namespace api
-} // namespace engine
 } // namespace osrm
 
 #endif // ENGINE_GUIDANCE_API_RESPONSE_GENERATOR_HPP_
diff --git a/include/engine/api/match_api.hpp b/include/engine/api/match_api.hpp
index d7899817d..341f9cc3b 100644
--- a/include/engine/api/match_api.hpp
+++ b/include/engine/api/match_api.hpp
@@ -12,11 +12,7 @@
 
 #include "util/integer_range.hpp"
 
-namespace osrm
-{
-namespace engine
-{
-namespace api
+namespace osrm::engine::api
 {
 
 class MatchAPI final : public RouteAPI
@@ -253,8 +249,6 @@ class MatchAPI final : public RouteAPI
     const tidy::Result &tidy_result;
 };
 
-} // namespace api
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/api/match_parameters.hpp b/include/engine/api/match_parameters.hpp
index 774a2c09d..e2009bd6e 100644
--- a/include/engine/api/match_parameters.hpp
+++ b/include/engine/api/match_parameters.hpp
@@ -32,11 +32,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace api
+namespace osrm::engine::api
 {
 
 /**
@@ -98,8 +94,6 @@ struct MatchParameters : public RouteParameters
                (timestamps.empty() || timestamps.size() == coordinates.size());
     }
 };
-} // namespace api
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/api/match_parameters_tidy.hpp b/include/engine/api/match_parameters_tidy.hpp
index 694dd6885..43b12dd13 100644
--- a/include/engine/api/match_parameters_tidy.hpp
+++ b/include/engine/api/match_parameters_tidy.hpp
@@ -11,13 +11,7 @@
 #include <boost/assert.hpp>
 #include <boost/dynamic_bitset.hpp>
 
-namespace osrm
-{
-namespace engine
-{
-namespace api
-{
-namespace tidy
+namespace osrm::engine::api::tidy
 {
 
 struct Thresholds
@@ -200,9 +194,6 @@ inline Result tidy(const MatchParameters &params, Thresholds cfg = {15., 5})
     return result;
 }
 
-} // namespace tidy
-} // namespace api
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/api/nearest_api.hpp b/include/engine/api/nearest_api.hpp
index 43c42de29..1f031f2f5 100644
--- a/include/engine/api/nearest_api.hpp
+++ b/include/engine/api/nearest_api.hpp
@@ -12,11 +12,7 @@
 
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace api
+namespace osrm::engine::api
 {
 
 class NearestAPI final : public BaseAPI
@@ -164,8 +160,6 @@ class NearestAPI final : public BaseAPI
     }
 };
 
-} // namespace api
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/api/nearest_parameters.hpp b/include/engine/api/nearest_parameters.hpp
index 576e75352..d6217fcfa 100644
--- a/include/engine/api/nearest_parameters.hpp
+++ b/include/engine/api/nearest_parameters.hpp
@@ -30,11 +30,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include "engine/api/base_parameters.hpp"
 
-namespace osrm
-{
-namespace engine
-{
-namespace api
+namespace osrm::engine::api
 {
 
 /**
@@ -52,8 +48,6 @@ struct NearestParameters : public BaseParameters
 
     bool IsValid() const { return BaseParameters::IsValid() && number_of_results >= 1; }
 };
-} // namespace api
-} // namespace engine
 } // namespace osrm
 
 #endif // ENGINE_API_NEAREST_PARAMETERS_HPP
diff --git a/include/engine/api/route_api.hpp b/include/engine/api/route_api.hpp
index 044ea0b1b..a494abe64 100644
--- a/include/engine/api/route_api.hpp
+++ b/include/engine/api/route_api.hpp
@@ -31,11 +31,7 @@
 #include <map>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace api
+namespace osrm::engine::api
 {
 
 class RouteAPI : public BaseAPI
@@ -1001,8 +997,6 @@ class RouteAPI : public BaseAPI
     }
 };
 
-} // namespace api
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/api/route_parameters.hpp b/include/engine/api/route_parameters.hpp
index 8d5dd9ae4..a513daad1 100644
--- a/include/engine/api/route_parameters.hpp
+++ b/include/engine/api/route_parameters.hpp
@@ -32,11 +32,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace api
+namespace osrm::engine::api
 {
 
 /**
@@ -211,8 +207,6 @@ inline RouteParameters::AnnotationsType operator|=(RouteParameters::AnnotationsT
 {
     return lhs = lhs | rhs;
 }
-} // namespace api
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/api/table_api.hpp b/include/engine/api/table_api.hpp
index 21dc80a28..2eaee214b 100644
--- a/include/engine/api/table_api.hpp
+++ b/include/engine/api/table_api.hpp
@@ -22,11 +22,7 @@
 
 #include <iterator>
 
-namespace osrm
-{
-namespace engine
-{
-namespace api
+namespace osrm::engine::api
 {
 
 class TableAPI final : public BaseAPI
@@ -422,8 +418,6 @@ class TableAPI final : public BaseAPI
     const TableParameters &parameters;
 };
 
-} // namespace api
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/api/table_parameters.hpp b/include/engine/api/table_parameters.hpp
index 4d3db980e..ea860652c 100644
--- a/include/engine/api/table_parameters.hpp
+++ b/include/engine/api/table_parameters.hpp
@@ -36,11 +36,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <iterator>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace api
+namespace osrm::engine::api
 {
 
 /**
@@ -166,8 +162,6 @@ inline TableParameters::AnnotationsType &operator|=(TableParameters::Annotations
 {
     return lhs = lhs | rhs;
 }
-} // namespace api
-} // namespace engine
 } // namespace osrm
 
 #endif // ENGINE_API_TABLE_PARAMETERS_HPP
diff --git a/include/engine/api/tile_parameters.hpp b/include/engine/api/tile_parameters.hpp
index e5328e7c7..2c5bafc27 100644
--- a/include/engine/api/tile_parameters.hpp
+++ b/include/engine/api/tile_parameters.hpp
@@ -30,11 +30,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include <cmath>
 
-namespace osrm
-{
-namespace engine
-{
-namespace api
+namespace osrm::engine::api
 {
 
 /**
@@ -70,8 +66,6 @@ struct TileParameters final
         return valid_x && valid_y && valid_z;
     }
 };
-} // namespace api
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/api/trip_api.hpp b/include/engine/api/trip_api.hpp
index fb8e5598b..74e17676b 100644
--- a/include/engine/api/trip_api.hpp
+++ b/include/engine/api/trip_api.hpp
@@ -10,11 +10,7 @@
 
 #include "util/integer_range.hpp"
 
-namespace osrm
-{
-namespace engine
-{
-namespace api
+namespace osrm::engine::api
 {
 
 class TripAPI final : public RouteAPI
@@ -180,8 +176,6 @@ class TripAPI final : public RouteAPI
     const TripParameters &parameters;
 };
 
-} // namespace api
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/api/trip_parameters.hpp b/include/engine/api/trip_parameters.hpp
index 84d6b861a..bffcae38c 100644
--- a/include/engine/api/trip_parameters.hpp
+++ b/include/engine/api/trip_parameters.hpp
@@ -33,11 +33,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <boost/optional.hpp>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace api
+namespace osrm::engine::api
 {
 
 /**
@@ -76,8 +72,6 @@ struct TripParameters : public RouteParameters
 
     bool IsValid() const { return RouteParameters::IsValid(); }
 };
-} // namespace api
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/approach.hpp b/include/engine/approach.hpp
index f7d671a9c..c5ee5182a 100644
--- a/include/engine/approach.hpp
+++ b/include/engine/approach.hpp
@@ -30,9 +30,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include <cstdint>
 
-namespace osrm
-{
-namespace engine
+namespace osrm::engine
 {
 
 enum class Approach : std::uint8_t
@@ -41,6 +39,5 @@ enum class Approach : std::uint8_t
     UNRESTRICTED = 1
 
 };
-}
 } // namespace osrm
 #endif
diff --git a/include/engine/bearing.hpp b/include/engine/bearing.hpp
index 54e24f57f..60bfe28fe 100644
--- a/include/engine/bearing.hpp
+++ b/include/engine/bearing.hpp
@@ -28,9 +28,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef OSRM_ENGINE_BEARING_HPP
 #define OSRM_ENGINE_BEARING_HPP
 
-namespace osrm
-{
-namespace engine
+namespace osrm::engine
 {
 
 struct Bearing
@@ -46,7 +44,6 @@ inline bool operator==(const Bearing lhs, const Bearing rhs)
     return lhs.bearing == rhs.bearing && lhs.range == rhs.range;
 }
 inline bool operator!=(const Bearing lhs, const Bearing rhs) { return !(lhs == rhs); }
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/data_watchdog.hpp b/include/engine/data_watchdog.hpp
index 29fb93443..1e913a26b 100644
--- a/include/engine/data_watchdog.hpp
+++ b/include/engine/data_watchdog.hpp
@@ -17,9 +17,7 @@
 #include <memory>
 #include <thread>
 
-namespace osrm
-{
-namespace engine
+namespace osrm::engine
 {
 
 namespace detail
@@ -149,7 +147,6 @@ class DataWatchdogImpl<AlgorithmT, datafacade::ContiguousInternalMemoryDataFacad
 // once a new dataset arrives.
 template <typename AlgorithmT, template <typename A> class FacadeT>
 using DataWatchdog = detail::DataWatchdogImpl<AlgorithmT, FacadeT<AlgorithmT>>;
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/datafacade.hpp b/include/engine/datafacade.hpp
index f0f8e9e5b..1488610e0 100644
--- a/include/engine/datafacade.hpp
+++ b/include/engine/datafacade.hpp
@@ -3,15 +3,12 @@
 
 #include "engine/datafacade/contiguous_internalmem_datafacade.hpp"
 
-namespace osrm
-{
-namespace engine
+namespace osrm::engine
 {
 
 using DataFacadeBase = datafacade::ContiguousInternalMemoryDataFacadeBase;
 template <typename AlgorithmT>
 using DataFacade = datafacade::ContiguousInternalMemoryDataFacade<AlgorithmT>;
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/datafacade/algorithm_datafacade.hpp b/include/engine/datafacade/algorithm_datafacade.hpp
index 73c6b4732..d838f9c09 100644
--- a/include/engine/datafacade/algorithm_datafacade.hpp
+++ b/include/engine/datafacade/algorithm_datafacade.hpp
@@ -12,11 +12,7 @@
 #include "util/filtered_graph.hpp"
 #include "util/integer_range.hpp"
 
-namespace osrm
-{
-namespace engine
-{
-namespace datafacade
+namespace osrm::engine::datafacade
 {
 
 // Namespace local aliases for algorithms
@@ -109,8 +105,6 @@ template <> class AlgorithmDataFacade<MLD>
     virtual EdgeID FindEdge(const NodeID edge_based_node_from,
                             const NodeID edge_based_node_to) const = 0;
 };
-} // namespace datafacade
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/datafacade/contiguous_block_allocator.hpp b/include/engine/datafacade/contiguous_block_allocator.hpp
index 0af5b310b..5103dc8a8 100644
--- a/include/engine/datafacade/contiguous_block_allocator.hpp
+++ b/include/engine/datafacade/contiguous_block_allocator.hpp
@@ -3,11 +3,7 @@
 
 #include "storage/shared_data_index.hpp"
 
-namespace osrm
-{
-namespace engine
-{
-namespace datafacade
+namespace osrm::engine::datafacade
 {
 
 class ContiguousBlockAllocator
@@ -19,8 +15,6 @@ class ContiguousBlockAllocator
     virtual const storage::SharedDataIndex &GetIndex() = 0;
 };
 
-} // namespace datafacade
-} // namespace engine
 } // namespace osrm
 
 #endif // OSRM_ENGINE_DATAFACADE_CONTIGUOUS_BLOCK_ALLOCATOR_HPP_
diff --git a/include/engine/datafacade/contiguous_internalmem_datafacade.hpp b/include/engine/datafacade/contiguous_internalmem_datafacade.hpp
index 48d00e0c1..936c9a927 100644
--- a/include/engine/datafacade/contiguous_internalmem_datafacade.hpp
+++ b/include/engine/datafacade/contiguous_internalmem_datafacade.hpp
@@ -28,11 +28,7 @@
 #include <utility>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace datafacade
+namespace osrm::engine::datafacade
 {
 
 template <typename AlgorithmT> class ContiguousInternalMemoryAlgorithmDataFacade;
@@ -693,8 +689,6 @@ class ContiguousInternalMemoryDataFacade<MLD> final
     {
     }
 };
-} // namespace datafacade
-} // namespace engine
 } // namespace osrm
 
 #endif // CONTIGUOUS_INTERNALMEM_DATAFACADE_HPP
diff --git a/include/engine/datafacade/datafacade_base.hpp b/include/engine/datafacade/datafacade_base.hpp
index 8ecd5946e..d38a329bf 100644
--- a/include/engine/datafacade/datafacade_base.hpp
+++ b/include/engine/datafacade/datafacade_base.hpp
@@ -40,11 +40,7 @@
 #include <utility>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace datafacade
+namespace osrm::engine::datafacade
 {
 
 class BaseDataFacade
@@ -189,8 +185,6 @@ class BaseDataFacade
     virtual std::vector<extractor::ManeuverOverride>
     GetOverridesThatStartAt(const NodeID edge_based_node_id) const = 0;
 };
-} // namespace datafacade
-} // namespace engine
 } // namespace osrm
 
 #endif // DATAFACADE_BASE_HPP
diff --git a/include/engine/datafacade/mmap_memory_allocator.hpp b/include/engine/datafacade/mmap_memory_allocator.hpp
index 817fcf9db..9fae0f562 100644
--- a/include/engine/datafacade/mmap_memory_allocator.hpp
+++ b/include/engine/datafacade/mmap_memory_allocator.hpp
@@ -12,11 +12,7 @@
 #include <memory>
 #include <string>
 
-namespace osrm
-{
-namespace engine
-{
-namespace datafacade
+namespace osrm::engine::datafacade
 {
 
 /**
@@ -37,8 +33,6 @@ class MMapMemoryAllocator final : public ContiguousBlockAllocator
     std::string rtree_filename;
 };
 
-} // namespace datafacade
-} // namespace engine
 } // namespace osrm
 
 #endif // OSRM_ENGINE_DATAFACADE_SHARED_MEMORY_ALLOCATOR_HPP_
diff --git a/include/engine/datafacade/process_memory_allocator.hpp b/include/engine/datafacade/process_memory_allocator.hpp
index 742f20e36..5851f545f 100644
--- a/include/engine/datafacade/process_memory_allocator.hpp
+++ b/include/engine/datafacade/process_memory_allocator.hpp
@@ -6,11 +6,7 @@
 
 #include <memory>
 
-namespace osrm
-{
-namespace engine
-{
-namespace datafacade
+namespace osrm::engine::datafacade
 {
 
 /**
@@ -34,8 +30,6 @@ class ProcessMemoryAllocator final : public ContiguousBlockAllocator
     std::unique_ptr<char[]> internal_memory;
 };
 
-} // namespace datafacade
-} // namespace engine
 } // namespace osrm
 
 #endif // OSRM_ENGINE_DATAFACADE_PROCESS_MEMORY_ALLOCATOR_HPP_
diff --git a/include/engine/datafacade/shared_memory_allocator.hpp b/include/engine/datafacade/shared_memory_allocator.hpp
index 5b0a0989a..5326d8d37 100644
--- a/include/engine/datafacade/shared_memory_allocator.hpp
+++ b/include/engine/datafacade/shared_memory_allocator.hpp
@@ -8,11 +8,7 @@
 
 #include <memory>
 
-namespace osrm
-{
-namespace engine
-{
-namespace datafacade
+namespace osrm::engine::datafacade
 {
 
 /**
@@ -35,8 +31,6 @@ class SharedMemoryAllocator final : public ContiguousBlockAllocator
     std::vector<std::unique_ptr<storage::SharedMemory>> memory_regions;
 };
 
-} // namespace datafacade
-} // namespace engine
 } // namespace osrm
 
 #endif // OSRM_ENGINE_DATAFACADE_SHARED_MEMORY_ALLOCATOR_HPP_
diff --git a/include/engine/datafacade_factory.hpp b/include/engine/datafacade_factory.hpp
index e01c70f72..705b8ff19 100644
--- a/include/engine/datafacade_factory.hpp
+++ b/include/engine/datafacade_factory.hpp
@@ -16,9 +16,7 @@
 #include <memory>
 #include <unordered_map>
 
-namespace osrm
-{
-namespace engine
+namespace osrm::engine
 {
 // This class selects the right facade for
 template <template <typename A> class FacadeT, typename AlgorithmT> class DataFacadeFactory
@@ -152,7 +150,6 @@ template <template <typename A> class FacadeT, typename AlgorithmT> class DataFa
     std::unordered_map<std::string, extractor::ClassData> name_to_class;
     const extractor::ProfileProperties *properties = nullptr;
 };
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/datafacade_provider.hpp b/include/engine/datafacade_provider.hpp
index 0ad6370f0..d5aae6433 100644
--- a/include/engine/datafacade_provider.hpp
+++ b/include/engine/datafacade_provider.hpp
@@ -8,9 +8,7 @@
 #include "engine/datafacade/process_memory_allocator.hpp"
 #include "engine/datafacade_factory.hpp"
 
-namespace osrm
-{
-namespace engine
+namespace osrm::engine
 {
 namespace detail
 {
@@ -103,7 +101,6 @@ template <typename AlgorithmT>
 using ImmutableProvider = detail::ImmutableProvider<AlgorithmT, DataFacade>;
 template <typename AlgorithmT>
 using ExternalProvider = detail::ExternalProvider<AlgorithmT, DataFacade>;
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/douglas_peucker.hpp b/include/engine/douglas_peucker.hpp
index 1dced2617..0348eab83 100644
--- a/include/engine/douglas_peucker.hpp
+++ b/include/engine/douglas_peucker.hpp
@@ -6,9 +6,7 @@
 #include <iterator>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
+namespace osrm::engine
 {
 namespace detail
 {
@@ -75,7 +73,6 @@ inline std::vector<util::Coordinate> douglasPeucker(const std::vector<util::Coor
 {
     return douglasPeucker(begin(geometry), end(geometry), zoom_level);
 }
-} // namespace engine
 } // namespace osrm
 
 #endif /* DOUGLAS_PEUCKER_HPP_ */
diff --git a/include/engine/engine.hpp b/include/engine/engine.hpp
index 451253df6..571eba979 100644
--- a/include/engine/engine.hpp
+++ b/include/engine/engine.hpp
@@ -23,9 +23,7 @@
 #include <memory>
 #include <string>
 
-namespace osrm
-{
-namespace engine
+namespace osrm::engine
 {
 
 class EngineInterface
@@ -130,7 +128,6 @@ template <typename Algorithm> class Engine final : public EngineInterface
     const plugins::MatchPlugin match_plugin;
     const plugins::TilePlugin tile_plugin;
 };
-} // namespace engine
 } // namespace osrm
 
 #endif // OSRM_IMPL_HPP
diff --git a/include/engine/engine_config.hpp b/include/engine/engine_config.hpp
index ece74b3a5..5edb25a02 100644
--- a/include/engine/engine_config.hpp
+++ b/include/engine/engine_config.hpp
@@ -34,10 +34,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include <string>
 
-namespace osrm
-{
-
-namespace engine
+namespace osrm::engine
 {
 
 /**
@@ -94,7 +91,6 @@ struct EngineConfig final
     std::string verbosity;
     std::string dataset_name;
 };
-} // namespace engine
 } // namespace osrm
 
 #endif // SERVER_CONFIG_HPP
diff --git a/include/engine/geospatial_query.hpp b/include/engine/geospatial_query.hpp
index 463841243..bb1365bbc 100644
--- a/include/engine/geospatial_query.hpp
+++ b/include/engine/geospatial_query.hpp
@@ -18,9 +18,7 @@
 #include <memory>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
+namespace osrm::engine
 {
 
 inline std::pair<bool, bool> operator&&(const std::pair<bool, bool> &a,
@@ -583,7 +581,6 @@ template <typename RTreeT, typename DataFacadeT> class GeospatialQuery
     const CoordinateList &coordinates;
     DataFacadeT &datafacade;
 };
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/guidance/assemble_geometry.hpp b/include/engine/guidance/assemble_geometry.hpp
index 7f616e13f..af4477f22 100644
--- a/include/engine/guidance/assemble_geometry.hpp
+++ b/include/engine/guidance/assemble_geometry.hpp
@@ -16,11 +16,7 @@
 #include <utility>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace guidance
+namespace osrm::engine::guidance
 {
 // Extracts the geometry for each segment and calculates the traveled distance
 // Combines the geometry form the phantom node with the PathData
@@ -172,8 +168,6 @@ inline LegGeometry assembleGeometry(const datafacade::BaseDataFacade &facade,
 
     return geometry;
 }
-} // namespace guidance
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/guidance/assemble_leg.hpp b/include/engine/guidance/assemble_leg.hpp
index 595f09b99..cec40e1f7 100644
--- a/include/engine/guidance/assemble_leg.hpp
+++ b/include/engine/guidance/assemble_leg.hpp
@@ -23,11 +23,7 @@
 #include <utility>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace guidance
+namespace osrm::engine::guidance
 {
 namespace detail
 {
@@ -232,8 +228,6 @@ inline RouteLeg assembleLeg(const datafacade::BaseDataFacade &facade,
                     {}};
 }
 
-} // namespace guidance
-} // namespace engine
 } // namespace osrm
 
 #endif // ENGINE_GUIDANCE_SEGMENT_LIST_HPP_
diff --git a/include/engine/guidance/assemble_overview.hpp b/include/engine/guidance/assemble_overview.hpp
index f801d6c22..b8ee72eba 100644
--- a/include/engine/guidance/assemble_overview.hpp
+++ b/include/engine/guidance/assemble_overview.hpp
@@ -7,18 +7,12 @@
 
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace guidance
+namespace osrm::engine::guidance
 {
 
 std::vector<util::Coordinate> assembleOverview(const std::vector<LegGeometry> &leg_geometries,
                                                const bool use_simplification);
 
-} // namespace guidance
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/guidance/assemble_route.hpp b/include/engine/guidance/assemble_route.hpp
index 82f4aa4de..cdec0e61b 100644
--- a/include/engine/guidance/assemble_route.hpp
+++ b/include/engine/guidance/assemble_route.hpp
@@ -6,17 +6,11 @@
 
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace guidance
+namespace osrm::engine::guidance
 {
 
 Route assembleRoute(const std::vector<RouteLeg> &route_legs);
 
-} // namespace guidance
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/guidance/assemble_steps.hpp b/include/engine/guidance/assemble_steps.hpp
index 2f1b06924..d5a0e5e14 100644
--- a/include/engine/guidance/assemble_steps.hpp
+++ b/include/engine/guidance/assemble_steps.hpp
@@ -22,11 +22,7 @@
 #include <guidance/turn_bearing.hpp>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace guidance
+namespace osrm::engine::guidance
 {
 namespace detail
 {
@@ -365,8 +361,6 @@ inline std::vector<RouteStep> assembleSteps(const datafacade::BaseDataFacade &fa
     return steps;
 }
 
-} // namespace guidance
-} // namespace engine
 } // namespace osrm
 
 #endif // ENGINE_GUIDANCE_SEGMENT_LIST_HPP_
diff --git a/include/engine/guidance/collapse_scenario_detection.hpp b/include/engine/guidance/collapse_scenario_detection.hpp
index b2f302339..958c91ba4 100644
--- a/include/engine/guidance/collapse_scenario_detection.hpp
+++ b/include/engine/guidance/collapse_scenario_detection.hpp
@@ -4,11 +4,7 @@
 #include "engine/guidance/collapsing_utility.hpp"
 #include "engine/guidance/route_step.hpp"
 
-namespace osrm
-{
-namespace engine
-{
-namespace guidance
+namespace osrm::engine::guidance
 {
 
 // check basic collapse preconditions (mode ok, no roundabout types);
@@ -87,8 +83,6 @@ bool doubleChoiceless(const RouteStepIterator step_entering_intersection,
 bool straightTurnFollowedByChoiceless(const RouteStepIterator step_entering_intersection,
                                       const RouteStepIterator step_leaving_intersection);
 
-} /* namespace guidance */
-} /* namespace engine */
 } /* namespace osrm */
 
 #endif /* OSRM_ENGINE_GUIDANCE_COLLAPSE_SCENARIO_DETECTION_HPP_ */
diff --git a/include/engine/guidance/collapse_turns.hpp b/include/engine/guidance/collapse_turns.hpp
index d2db4a420..ffde35d4d 100644
--- a/include/engine/guidance/collapse_turns.hpp
+++ b/include/engine/guidance/collapse_turns.hpp
@@ -6,11 +6,7 @@
 #include <type_traits>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace guidance
+namespace osrm::engine::guidance
 {
 
 // Multiple possible reasons can result in unnecessary/confusing instructions
@@ -162,8 +158,6 @@ void combineRouteSteps(RouteStep &step_at_turn_location,
 // alias for suppressing a step, using CombineRouteStep with NoModificationStrategy only
 void suppressStep(RouteStep &step_at_turn_location, RouteStep &step_after_turn_location);
 
-} /* namespace guidance */
-} // namespace engine
 } /* namespace osrm */
 
 #endif /* OSRM_ENGINE_GUIDANCE_COLLAPSE_HPP_ */
diff --git a/include/engine/guidance/collapsing_utility.hpp b/include/engine/guidance/collapsing_utility.hpp
index 51ed8999b..7a61aba24 100644
--- a/include/engine/guidance/collapsing_utility.hpp
+++ b/include/engine/guidance/collapsing_utility.hpp
@@ -10,11 +10,7 @@
 #include <boost/range/algorithm_ext/erase.hpp>
 #include <cstddef>
 
-namespace osrm
-{
-namespace engine
-{
-namespace guidance
+namespace osrm::engine::guidance
 {
 
 using RouteSteps = std::vector<RouteStep>;
@@ -302,8 +298,6 @@ inline bool hasStraightestTurn(const RouteStep &step)
     return false;
 }
 
-} /* namespace guidance */
-} /* namespace engine */
 } /* namespace osrm */
 
 #endif /* OSRM_ENGINE_GUIDANCE_COLLAPSING_UTILITY_HPP_ */
diff --git a/include/engine/guidance/lane_processing.hpp b/include/engine/guidance/lane_processing.hpp
index ce3d6cb8a..4c9d0dc3d 100644
--- a/include/engine/guidance/lane_processing.hpp
+++ b/include/engine/guidance/lane_processing.hpp
@@ -6,11 +6,7 @@
 #include "engine/guidance/route_step.hpp"
 #include "util/attributes.hpp"
 
-namespace osrm
-{
-namespace engine
-{
-namespace guidance
+namespace osrm::engine::guidance
 {
 
 // Constrains lanes for multi-hop situations where lane changes depend on earlier ones.
@@ -22,8 +18,6 @@ OSRM_ATTR_WARN_UNUSED
 std::vector<RouteStep> anticipateLaneChange(std::vector<RouteStep> steps,
                                             const double min_distance_needed_for_lane_change = 200);
 
-} // namespace guidance
-} // namespace engine
 } // namespace osrm
 
 #endif /* OSRM_ENGINE_GUIDANCE_LANE_PROCESSING_HPP_ */
diff --git a/include/engine/guidance/leg_geometry.hpp b/include/engine/guidance/leg_geometry.hpp
index 78ebd42ad..fcfd5cf2c 100644
--- a/include/engine/guidance/leg_geometry.hpp
+++ b/include/engine/guidance/leg_geometry.hpp
@@ -12,11 +12,7 @@
 #include <cstdlib>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace guidance
+namespace osrm::engine::guidance
 {
 
 // locations 0---1---2-...-n-1---n
@@ -64,8 +60,6 @@ struct LegGeometry
         return segment_offsets.size() - 1;
     }
 };
-} // namespace guidance
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/guidance/post_processing.hpp b/include/engine/guidance/post_processing.hpp
index 7bf6967ad..8b0bcb18e 100644
--- a/include/engine/guidance/post_processing.hpp
+++ b/include/engine/guidance/post_processing.hpp
@@ -9,11 +9,7 @@
 
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace guidance
+namespace osrm::engine::guidance
 {
 
 // passed as none-reference to modify in-place and move out again
@@ -58,8 +54,6 @@ void applyOverrides(const datafacade::BaseDataFacade &facade,
                     std::vector<RouteStep> &steps,
                     const LegGeometry &geometry);
 
-} // namespace guidance
-} // namespace engine
 } // namespace osrm
 
 #endif // ENGINE_GUIDANCE_POST_PROCESSING_HPP
diff --git a/include/engine/guidance/postprocessing_toolkit.hpp b/include/engine/guidance/postprocessing_toolkit.hpp
index 24f485fc1..f4e993540 100644
--- a/include/engine/guidance/postprocessing_toolkit.hpp
+++ b/include/engine/guidance/postprocessing_toolkit.hpp
@@ -7,11 +7,7 @@
 #include <iterator>
 #include <utility>
 
-namespace osrm
-{
-namespace engine
-{
-namespace guidance
+namespace osrm::engine::guidance
 {
 
 // Runs fn on RouteStep sub-ranges determined to be roundabouts.
@@ -46,8 +42,6 @@ template <typename Iter, typename Fn> inline Fn forEachRoundabout(Iter first, It
     return fn;
 }
 
-} // namespace guidance
-} // namespace engine
 } // namespace osrm
 
 #endif /* OSRM_ENGINE_GUIDANCE_POSTPROCESSING_TOOLKIT_HPP_ */
diff --git a/include/engine/guidance/route.hpp b/include/engine/guidance/route.hpp
index fa750d4da..e831fb12d 100644
--- a/include/engine/guidance/route.hpp
+++ b/include/engine/guidance/route.hpp
@@ -1,11 +1,7 @@
 #ifndef ROUTE_HPP
 #define ROUTE_HPP
 
-namespace osrm
-{
-namespace engine
-{
-namespace guidance
+namespace osrm::engine::guidance
 {
 
 struct Route
@@ -14,8 +10,6 @@ struct Route
     double duration;
     double weight;
 };
-} // namespace guidance
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/guidance/route_leg.hpp b/include/engine/guidance/route_leg.hpp
index 443c2ae23..c8d4cfa9b 100644
--- a/include/engine/guidance/route_leg.hpp
+++ b/include/engine/guidance/route_leg.hpp
@@ -8,11 +8,7 @@
 #include <string>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace guidance
+namespace osrm::engine::guidance
 {
 
 struct RouteLeg
@@ -23,8 +19,6 @@ struct RouteLeg
     std::string summary;
     std::vector<RouteStep> steps;
 };
-} // namespace guidance
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/guidance/route_step.hpp b/include/engine/guidance/route_step.hpp
index 48a6d9b49..7d9c50927 100644
--- a/include/engine/guidance/route_step.hpp
+++ b/include/engine/guidance/route_step.hpp
@@ -16,11 +16,7 @@
 
 #include <boost/range/iterator_range.hpp>
 
-namespace osrm
-{
-namespace engine
-{
-namespace guidance
+namespace osrm::engine::guidance
 {
 // Given the following turn from a,b to b,c over b:
 //  a --> b --> c
@@ -234,8 +230,6 @@ inline auto RouteStep::LanesToTheRight() const
     return boost::make_iterator_range(description.end() - num_lanes_right, description.end());
 }
 
-} // namespace guidance
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/guidance/step_maneuver.hpp b/include/engine/guidance/step_maneuver.hpp
index efe0726ca..2e68f8394 100644
--- a/include/engine/guidance/step_maneuver.hpp
+++ b/include/engine/guidance/step_maneuver.hpp
@@ -8,11 +8,7 @@
 #include <string>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace guidance
+namespace osrm::engine::guidance
 {
 
 enum class WaypointType : std::uint8_t
@@ -44,7 +40,5 @@ inline StepManeuver getInvalidStepManeuver()
             0};
 }
 
-} // namespace guidance
-} // namespace engine
 } // namespace osrm
 #endif
diff --git a/include/engine/guidance/verbosity_reduction.hpp b/include/engine/guidance/verbosity_reduction.hpp
index d10f3af4a..6e29e5acc 100644
--- a/include/engine/guidance/verbosity_reduction.hpp
+++ b/include/engine/guidance/verbosity_reduction.hpp
@@ -6,11 +6,7 @@
 
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace guidance
+namespace osrm::engine::guidance
 {
 
 // Name changes on roads are posing relevant information. However if they are short, we don't want
@@ -20,8 +16,6 @@ namespace guidance
 OSRM_ATTR_WARN_UNUSED
 std::vector<RouteStep> suppressShortNameSegments(std::vector<RouteStep> steps);
 
-} // namespace guidance
-} // namespace engine
 } // namespace osrm
 
 #endif /* OSRM_ENGINE_GUIDANCE_VERBOSITY_REDUCTION_HPP_ */
diff --git a/include/engine/hint.hpp b/include/engine/hint.hpp
index 58b801840..7428e29a5 100644
--- a/include/engine/hint.hpp
+++ b/include/engine/hint.hpp
@@ -36,9 +36,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <iosfwd>
 #include <string>
 
-namespace osrm
-{
-namespace engine
+namespace osrm::engine
 {
 
 // Fwd. decls.
@@ -83,7 +81,6 @@ constexpr std::size_t ENCODED_SEGMENT_HINT_SIZE = 112;
 static_assert(ENCODED_SEGMENT_HINT_SIZE / 4 * 3 >= sizeof(SegmentHint),
               "ENCODED_SEGMENT_HINT_SIZE does not match size of SegmentHint");
 
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/internal_route_result.hpp b/include/engine/internal_route_result.hpp
index 6c0cdcc89..cdecc9e59 100644
--- a/include/engine/internal_route_result.hpp
+++ b/include/engine/internal_route_result.hpp
@@ -18,9 +18,7 @@
 #include <boost/optional.hpp>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
+namespace osrm::engine
 {
 
 struct PathData
@@ -152,7 +150,6 @@ inline InternalRouteResult CollapseInternalRouteResult(const InternalRouteResult
     BOOST_ASSERT(collapsed.leg_endpoints.size() == collapsed.unpacked_path_segments.size());
     return collapsed;
 }
-} // namespace engine
 } // namespace osrm
 
 #endif // RAW_ROUTE_DATA_H
diff --git a/include/engine/map_matching/bayes_classifier.hpp b/include/engine/map_matching/bayes_classifier.hpp
index c93277f64..da1d3d5c6 100644
--- a/include/engine/map_matching/bayes_classifier.hpp
+++ b/include/engine/map_matching/bayes_classifier.hpp
@@ -8,11 +8,7 @@
 
 #include <boost/math/constants/constants.hpp>
 
-namespace osrm
-{
-namespace engine
-{
-namespace map_matching
+namespace osrm::engine::map_matching
 {
 
 struct NormalDistribution
@@ -98,8 +94,6 @@ class BayesClassifier
     double positive_apriori_probability;
     double negative_apriori_probability;
 };
-} // namespace map_matching
-} // namespace engine
 } // namespace osrm
 
 #endif // BAYES_CLASSIFIER_HPP
diff --git a/include/engine/map_matching/hidden_markov_model.hpp b/include/engine/map_matching/hidden_markov_model.hpp
index 30bb8254b..c2c7a3eca 100644
--- a/include/engine/map_matching/hidden_markov_model.hpp
+++ b/include/engine/map_matching/hidden_markov_model.hpp
@@ -11,11 +11,7 @@
 #include <limits>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace map_matching
+namespace osrm::engine::map_matching
 {
 
 static const double log_2_pi = std::log(2. * boost::math::constants::pi<double>());
@@ -137,8 +133,6 @@ template <class CandidateLists> struct HiddenMarkovModel
         return initial_timestamp;
     }
 };
-} // namespace map_matching
-} // namespace engine
 } // namespace osrm
 
 #endif // HIDDEN_MARKOV_MODEL
diff --git a/include/engine/map_matching/matching_confidence.hpp b/include/engine/map_matching/matching_confidence.hpp
index 2ae8728d6..dd65f397b 100644
--- a/include/engine/map_matching/matching_confidence.hpp
+++ b/include/engine/map_matching/matching_confidence.hpp
@@ -5,11 +5,7 @@
 
 #include <cmath>
 
-namespace osrm
-{
-namespace engine
-{
-namespace map_matching
+namespace osrm::engine::map_matching
 {
 
 struct MatchingConfidence
@@ -51,8 +47,6 @@ struct MatchingConfidence
   private:
     ClassifierT classifier;
 };
-} // namespace map_matching
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/map_matching/sub_matching.hpp b/include/engine/map_matching/sub_matching.hpp
index 544978d61..b099fb3a3 100644
--- a/include/engine/map_matching/sub_matching.hpp
+++ b/include/engine/map_matching/sub_matching.hpp
@@ -5,11 +5,7 @@
 
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace map_matching
+namespace osrm::engine::map_matching
 {
 
 struct SubMatching
@@ -19,8 +15,6 @@ struct SubMatching
     std::vector<unsigned> alternatives_count;
     double confidence;
 };
-} // namespace map_matching
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/phantom_node.hpp b/include/engine/phantom_node.hpp
index f7ca5b82e..107d78ea8 100644
--- a/include/engine/phantom_node.hpp
+++ b/include/engine/phantom_node.hpp
@@ -25,8 +25,8 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 */
 
-#ifndef OSRM_ENGINE_PHANTOM_NODES_H
-#define OSRM_ENGINE_PHANTOM_NODES_H
+#ifndef OSRM_ENGINE_PHANTOM_NODE_H
+#define OSRM_ENGINE_PHANTOM_NODE_H
 
 #include <vector>
 
@@ -38,9 +38,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include <boost/assert.hpp>
 
-namespace osrm
-{
-namespace engine
+namespace osrm::engine
 {
 
 struct PhantomNode
@@ -273,7 +271,6 @@ struct PhantomEndpoints
     PhantomNode target_phantom;
 };
 
-} // namespace engine
 } // namespace osrm
 
-#endif // PHANTOM_NODES_H
+#endif // OSRM_ENGINE_PHANTOM_NODE_H
diff --git a/include/engine/plugins/match.hpp b/include/engine/plugins/match.hpp
index 5b2bdca30..ff88c462c 100644
--- a/include/engine/plugins/match.hpp
+++ b/include/engine/plugins/match.hpp
@@ -9,11 +9,7 @@
 
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace plugins
+namespace osrm::engine::plugins
 {
 
 class MatchPlugin : public BasePlugin
@@ -38,8 +34,6 @@ class MatchPlugin : public BasePlugin
     const int max_locations_map_matching;
     const double max_radius_map_matching;
 };
-} // namespace plugins
-} // namespace engine
 } // namespace osrm
 
 #endif // MATCH_HPP
diff --git a/include/engine/plugins/nearest.hpp b/include/engine/plugins/nearest.hpp
index 4582de348..ff812e885 100644
--- a/include/engine/plugins/nearest.hpp
+++ b/include/engine/plugins/nearest.hpp
@@ -7,11 +7,7 @@
 #include "engine/routing_algorithms.hpp"
 #include "osrm/json_container.hpp"
 
-namespace osrm
-{
-namespace engine
-{
-namespace plugins
+namespace osrm::engine::plugins
 {
 
 class NearestPlugin final : public BasePlugin
@@ -26,8 +22,6 @@ class NearestPlugin final : public BasePlugin
   private:
     const int max_results;
 };
-} // namespace plugins
-} // namespace engine
 } // namespace osrm
 
 #endif /* NEAREST_HPP */
diff --git a/include/engine/plugins/plugin_base.hpp b/include/engine/plugins/plugin_base.hpp
index 11700e52b..91ad15461 100644
--- a/include/engine/plugins/plugin_base.hpp
+++ b/include/engine/plugins/plugin_base.hpp
@@ -21,11 +21,7 @@
 
 #include <util/log.hpp>
 
-namespace osrm
-{
-namespace engine
-{
-namespace plugins
+namespace osrm::engine::plugins
 {
 
 class BasePlugin
@@ -325,8 +321,6 @@ class BasePlugin
                std::to_string(missing_index);
     }
 };
-} // namespace plugins
-} // namespace engine
 } // namespace osrm
 
 #endif /* BASE_PLUGIN_HPP */
diff --git a/include/engine/plugins/table.hpp b/include/engine/plugins/table.hpp
index d8e5a32e9..9dfce38b0 100644
--- a/include/engine/plugins/table.hpp
+++ b/include/engine/plugins/table.hpp
@@ -8,11 +8,7 @@
 
 #include "util/json_container.hpp"
 
-namespace osrm
-{
-namespace engine
-{
-namespace plugins
+namespace osrm::engine::plugins
 {
 
 class TablePlugin final : public BasePlugin
@@ -27,8 +23,6 @@ class TablePlugin final : public BasePlugin
   private:
     const int max_locations_distance_table;
 };
-} // namespace plugins
-} // namespace engine
 } // namespace osrm
 
 #endif // TABLE_HPP
diff --git a/include/engine/plugins/tile.hpp b/include/engine/plugins/tile.hpp
index 5d4bdb5b0..dc22e7070 100644
--- a/include/engine/plugins/tile.hpp
+++ b/include/engine/plugins/tile.hpp
@@ -16,11 +16,7 @@
  * OSRM is routing.  This is very useful for debugging routing
  * errors
  */
-namespace osrm
-{
-namespace engine
-{
-namespace plugins
+namespace osrm::engine::plugins
 {
 
 class TilePlugin final : public BasePlugin
@@ -30,8 +26,6 @@ class TilePlugin final : public BasePlugin
                          const api::TileParameters &parameters,
                          osrm::engine::api::ResultT &pbf_buffer) const;
 };
-} // namespace plugins
-} // namespace engine
 } // namespace osrm
 
 #endif /* TILEPLUGIN_HPP */
diff --git a/include/engine/plugins/trip.hpp b/include/engine/plugins/trip.hpp
index cd8ffb5a4..2c4347f9c 100644
--- a/include/engine/plugins/trip.hpp
+++ b/include/engine/plugins/trip.hpp
@@ -18,11 +18,7 @@
 #include <utility>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace plugins
+namespace osrm::engine::plugins
 {
 
 class TripPlugin final : public BasePlugin
@@ -42,8 +38,6 @@ class TripPlugin final : public BasePlugin
                          const api::TripParameters &parameters,
                          osrm::engine::api::ResultT &json_result) const;
 };
-} // namespace plugins
-} // namespace engine
 } // namespace osrm
 
 #endif // TRIP_HPP
diff --git a/include/engine/plugins/viaroute.hpp b/include/engine/plugins/viaroute.hpp
index 719749472..a9382e05d 100644
--- a/include/engine/plugins/viaroute.hpp
+++ b/include/engine/plugins/viaroute.hpp
@@ -15,11 +15,7 @@
 #include <string>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace plugins
+namespace osrm::engine::plugins
 {
 
 class ViaRoutePlugin final : public BasePlugin
@@ -35,8 +31,6 @@ class ViaRoutePlugin final : public BasePlugin
                          const api::RouteParameters &route_parameters,
                          osrm::engine::api::ResultT &json_result) const;
 };
-} // namespace plugins
-} // namespace engine
 } // namespace osrm
 
 #endif // VIA_ROUTE_HPP
diff --git a/include/engine/polyline_compressor.hpp b/include/engine/polyline_compressor.hpp
index 224f1ed3b..cbda68e12 100644
--- a/include/engine/polyline_compressor.hpp
+++ b/include/engine/polyline_compressor.hpp
@@ -8,9 +8,7 @@
 #include <string>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
+namespace osrm::engine
 {
 namespace detail
 {
@@ -80,7 +78,6 @@ std::vector<util::Coordinate> decodePolyline(const std::string &polyline)
     }
     return coordinates;
 }
-} // namespace engine
 } // namespace osrm
 
 #endif /* POLYLINECOMPRESSOR_H_ */
diff --git a/include/engine/routing_algorithms.hpp b/include/engine/routing_algorithms.hpp
index 0253ef13c..c06e7ec75 100644
--- a/include/engine/routing_algorithms.hpp
+++ b/include/engine/routing_algorithms.hpp
@@ -11,9 +11,7 @@
 #include "engine/routing_algorithms/shortest_path.hpp"
 #include "engine/routing_algorithms/tile_turns.hpp"
 
-namespace osrm
-{
-namespace engine
+namespace osrm::engine
 {
 
 class RoutingAlgorithmsInterface
@@ -232,7 +230,6 @@ inline std::vector<routing_algorithms::TurnData> RoutingAlgorithms<Algorithm>::G
     return routing_algorithms::getTileTurns(*facade, edges, sorted_edge_indexes);
 }
 
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/routing_algorithms/alternative_path.hpp b/include/engine/routing_algorithms/alternative_path.hpp
index 25cc339eb..007510be8 100644
--- a/include/engine/routing_algorithms/alternative_path.hpp
+++ b/include/engine/routing_algorithms/alternative_path.hpp
@@ -9,11 +9,7 @@
 
 #include "util/exception.hpp"
 
-namespace osrm
-{
-namespace engine
-{
-namespace routing_algorithms
+namespace osrm::engine::routing_algorithms
 {
 
 InternalManyRoutesResult alternativePathSearch(SearchEngineData<ch::Algorithm> &search_engine_data,
@@ -26,8 +22,6 @@ InternalManyRoutesResult alternativePathSearch(SearchEngineData<mld::Algorithm>
                                                const PhantomEndpointCandidates &endpoint_candidates,
                                                unsigned number_of_alternatives);
 
-} // namespace routing_algorithms
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/routing_algorithms/direct_shortest_path.hpp b/include/engine/routing_algorithms/direct_shortest_path.hpp
index a6bb44df2..744f6da84 100644
--- a/include/engine/routing_algorithms/direct_shortest_path.hpp
+++ b/include/engine/routing_algorithms/direct_shortest_path.hpp
@@ -8,11 +8,7 @@
 
 #include "util/typedefs.hpp"
 
-namespace osrm
-{
-namespace engine
-{
-namespace routing_algorithms
+namespace osrm::engine::routing_algorithms
 {
 
 /// This is a stripped down version of the general shortest path algorithm.
@@ -26,8 +22,6 @@ InternalRouteResult directShortestPathSearch(SearchEngineData<Algorithm> &engine
                                              const DataFacade<Algorithm> &facade,
                                              const PhantomEndpointCandidates &endpoint_candidates);
 
-} // namespace routing_algorithms
-} // namespace engine
 } // namespace osrm
 
 #endif /* DIRECT_SHORTEST_PATH_HPP */
diff --git a/include/engine/routing_algorithms/many_to_many.hpp b/include/engine/routing_algorithms/many_to_many.hpp
index 96d4f973d..e5ae497c8 100644
--- a/include/engine/routing_algorithms/many_to_many.hpp
+++ b/include/engine/routing_algorithms/many_to_many.hpp
@@ -9,11 +9,7 @@
 
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace routing_algorithms
+namespace osrm::engine::routing_algorithms
 {
 namespace
 {
@@ -99,8 +95,6 @@ manyToManySearch(SearchEngineData<Algorithm> &engine_working_data,
                  const std::vector<std::size_t> &target_indices,
                  const bool calculate_distance);
 
-} // namespace routing_algorithms
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/routing_algorithms/map_matching.hpp b/include/engine/routing_algorithms/map_matching.hpp
index 359a06340..146405143 100644
--- a/include/engine/routing_algorithms/map_matching.hpp
+++ b/include/engine/routing_algorithms/map_matching.hpp
@@ -8,11 +8,7 @@
 
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace routing_algorithms
+namespace osrm::engine::routing_algorithms
 {
 
 using CandidateList = std::vector<PhantomNodeWithDistance>;
@@ -31,8 +27,6 @@ SubMatchingList mapMatching(SearchEngineData<Algorithm> &engine_working_data,
                             const std::vector<boost::optional<double>> &trace_gps_precision,
                             const bool allow_splitting);
 
-} // namespace routing_algorithms
-} // namespace engine
 } // namespace osrm
 
 #endif /* MAP_MATCHING_HPP */
diff --git a/include/engine/routing_algorithms/routing_base.hpp b/include/engine/routing_algorithms/routing_base.hpp
index 7be626092..473870fdf 100644
--- a/include/engine/routing_algorithms/routing_base.hpp
+++ b/include/engine/routing_algorithms/routing_base.hpp
@@ -27,12 +27,7 @@
 #include <utility>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-
-namespace routing_algorithms
+namespace osrm::engine::routing_algorithms
 {
 
 namespace details
@@ -421,8 +416,6 @@ template <typename FacadeT> EdgeDistance computeEdgeDistance(const FacadeT &faca
     return total_distance;
 }
 
-} // namespace routing_algorithms
-} // namespace engine
 } // namespace osrm
 
 #endif // OSRM_ENGINE_ROUTING_BASE_HPP
diff --git a/include/engine/routing_algorithms/routing_base_ch.hpp b/include/engine/routing_algorithms/routing_base_ch.hpp
index 410f7f464..c2a415534 100644
--- a/include/engine/routing_algorithms/routing_base_ch.hpp
+++ b/include/engine/routing_algorithms/routing_base_ch.hpp
@@ -10,15 +10,7 @@
 
 #include <boost/assert.hpp>
 
-namespace osrm
-{
-namespace engine
-{
-
-namespace routing_algorithms
-{
-
-namespace ch
+namespace osrm::engine::routing_algorithms::ch
 {
 
 // Stalling
@@ -522,9 +514,6 @@ std::tuple<EdgeMetric, EdgeDistance> getLoopMetric(const DataFacade<Algorithm> &
     }
     return std::make_tuple(loop_metric, loop_distance);
 }
-} // namespace ch
-} // namespace routing_algorithms
-} // namespace engine
 } // namespace osrm
 
 #endif // OSRM_ENGINE_ROUTING_BASE_CH_HPP
diff --git a/include/engine/routing_algorithms/routing_base_mld.hpp b/include/engine/routing_algorithms/routing_base_mld.hpp
index 72bbd7608..b20117e3c 100644
--- a/include/engine/routing_algorithms/routing_base_mld.hpp
+++ b/include/engine/routing_algorithms/routing_base_mld.hpp
@@ -16,13 +16,7 @@
 #include <tuple>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace routing_algorithms
-{
-namespace mld
+namespace osrm::engine::routing_algorithms::mld
 {
 
 namespace
@@ -655,9 +649,6 @@ double getNetworkDistance(SearchEngineData<Algorithm> &engine_working_data,
     return getPathDistance(facade, unpacked_path, source_phantom, target_phantom);
 }
 
-} // namespace mld
-} // namespace routing_algorithms
-} // namespace engine
 } // namespace osrm
 
 #endif // OSRM_ENGINE_ROUTING_BASE_MLD_HPP
diff --git a/include/engine/routing_algorithms/shortest_path.hpp b/include/engine/routing_algorithms/shortest_path.hpp
index fadf59a45..8e461de20 100644
--- a/include/engine/routing_algorithms/shortest_path.hpp
+++ b/include/engine/routing_algorithms/shortest_path.hpp
@@ -6,11 +6,7 @@
 #include "engine/search_engine_data.hpp"
 #include "util/typedefs.hpp"
 
-namespace osrm
-{
-namespace engine
-{
-namespace routing_algorithms
+namespace osrm::engine::routing_algorithms
 {
 
 template <typename Algorithm>
@@ -20,8 +16,6 @@ shortestPathSearch(SearchEngineData<Algorithm> &engine_working_data,
                    const std::vector<PhantomNodeCandidates> &waypoint_candidates,
                    const boost::optional<bool> continue_straight_at_waypoint);
 
-} // namespace routing_algorithms
-} // namespace engine
 } // namespace osrm
 
 #endif /* OSRM_SHORTEST_PATH_HPP */
diff --git a/include/engine/routing_algorithms/shortest_path_impl.hpp b/include/engine/routing_algorithms/shortest_path_impl.hpp
index 6206fed16..6aade1152 100644
--- a/include/engine/routing_algorithms/shortest_path_impl.hpp
+++ b/include/engine/routing_algorithms/shortest_path_impl.hpp
@@ -6,11 +6,7 @@
 #include <boost/assert.hpp>
 #include <boost/optional.hpp>
 
-namespace osrm
-{
-namespace engine
-{
-namespace routing_algorithms
+namespace osrm::engine::routing_algorithms
 {
 
 namespace
@@ -789,8 +785,6 @@ shortestPathSearch(SearchEngineData<Algorithm> &engine_working_data,
     }
 }
 
-} // namespace routing_algorithms
-} // namespace engine
 } // namespace osrm
 
 #endif /* OSRM_SHORTEST_PATH_IMPL_HPP */
diff --git a/include/engine/routing_algorithms/tile_turns.hpp b/include/engine/routing_algorithms/tile_turns.hpp
index ffa86c412..69f9ef102 100644
--- a/include/engine/routing_algorithms/tile_turns.hpp
+++ b/include/engine/routing_algorithms/tile_turns.hpp
@@ -9,11 +9,7 @@
 
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace routing_algorithms
+namespace osrm::engine::routing_algorithms
 {
 
 // Used to accumulate all the information we want in the tile about a turn.
@@ -37,8 +33,6 @@ std::vector<TurnData> getTileTurns(const DataFacade<mld::Algorithm> &facade,
                                    const std::vector<RTreeLeaf> &edges,
                                    const std::vector<std::size_t> &sorted_edge_indexes);
 
-} // namespace routing_algorithms
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/search_engine_data.hpp b/include/engine/search_engine_data.hpp
index 103c34fbd..cd809e7fd 100644
--- a/include/engine/search_engine_data.hpp
+++ b/include/engine/search_engine_data.hpp
@@ -7,9 +7,7 @@
 
 #include <boost/thread/tss.hpp>
 
-namespace osrm
-{
-namespace engine
+namespace osrm::engine
 {
 
 // Algorithm-dependent heaps
@@ -120,7 +118,6 @@ template <> struct SearchEngineData<routing_algorithms::mld::Algorithm>
     void InitializeOrClearManyToManyThreadLocalStorage(unsigned number_of_nodes,
                                                        unsigned number_of_boundary_nodes);
 };
-} // namespace engine
 } // namespace osrm
 
 #endif // SEARCH_ENGINE_DATA_HPP
diff --git a/include/engine/status.hpp b/include/engine/status.hpp
index 7b08db1d6..71c9eead0 100644
--- a/include/engine/status.hpp
+++ b/include/engine/status.hpp
@@ -28,9 +28,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef ENGINE_STATUS_HPP
 #define ENGINE_STATUS_HPP
 
-namespace osrm
-{
-namespace engine
+namespace osrm::engine
 {
 
 /**
@@ -42,7 +40,6 @@ enum class Status
     Ok,
     Error
 };
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/include/engine/trip/trip_brute_force.hpp b/include/engine/trip/trip_brute_force.hpp
index 1d3492546..148496de5 100644
--- a/include/engine/trip/trip_brute_force.hpp
+++ b/include/engine/trip/trip_brute_force.hpp
@@ -15,11 +15,7 @@
 #include <string>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace trip
+namespace osrm::engine::trip
 {
 
 // computes the distance of a given permutation
@@ -93,8 +89,6 @@ inline std::vector<NodeID> BruteForceTrip(const std::size_t number_of_locations,
     return route;
 }
 
-} // namespace trip
-} // namespace engine
 } // namespace osrm
 
 #endif // TRIP_BRUTE_FORCE_HPP
diff --git a/include/engine/trip/trip_farthest_insertion.hpp b/include/engine/trip/trip_farthest_insertion.hpp
index 21d7deefe..af0b95daa 100644
--- a/include/engine/trip/trip_farthest_insertion.hpp
+++ b/include/engine/trip/trip_farthest_insertion.hpp
@@ -13,11 +13,7 @@
 #include <string>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace trip
+namespace osrm::engine::trip
 {
 
 // given a route and a new location, find the best place of insertion and
@@ -175,8 +171,6 @@ FarthestInsertionTrip(const std::size_t number_of_locations,
     return FindRoute(number_of_locations, dist_table, max_from, max_to);
 }
 
-} // namespace trip
-} // namespace engine
 } // namespace osrm
 
 #endif // TRIP_FARTHEST_INSERTION_HPP
diff --git a/include/engine/trip/trip_nearest_neighbour.hpp b/include/engine/trip/trip_nearest_neighbour.hpp
index 29aca8e72..038a0fccf 100644
--- a/include/engine/trip/trip_nearest_neighbour.hpp
+++ b/include/engine/trip/trip_nearest_neighbour.hpp
@@ -13,11 +13,7 @@
 #include <string>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace trip
+namespace osrm::engine::trip
 {
 
 template <typename NodeIDIterator>
@@ -92,8 +88,6 @@ std::vector<NodeID> NearestNeighbourTrip(const NodeIDIterator &start,
     }
     return route;
 }
-} // namespace trip
-} // namespace engine
 } // namespace osrm
 
 #endif // TRIP_NEAREST_NEIGHBOUR_HPP
diff --git a/include/extractor/class_data.hpp b/include/extractor/class_data.hpp
index 5e5cf3087..1b685562f 100644
--- a/include/extractor/class_data.hpp
+++ b/include/extractor/class_data.hpp
@@ -7,9 +7,7 @@
 #include <cctype>
 #include <cstdint>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 using ClassData = std::uint8_t;
@@ -33,7 +31,6 @@ inline bool isValidClassName(const std::string &name)
                return std::isalnum(c);
            }) == name.end();
 }
-} // namespace extractor
 } // namespace osrm
 
 #endif
diff --git a/include/extractor/compressed_edge_container.hpp b/include/extractor/compressed_edge_container.hpp
index a0dc4d994..5254f6aa9 100644
--- a/include/extractor/compressed_edge_container.hpp
+++ b/include/extractor/compressed_edge_container.hpp
@@ -10,9 +10,7 @@
 #include <string>
 #include <vector>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 class CompressedEdgeContainer
@@ -82,7 +80,6 @@ class CompressedEdgeContainer
     std::unordered_map<EdgeID, unsigned> m_reverse_edge_id_to_zipped_index_map;
     std::unique_ptr<SegmentDataContainer> segment_data;
 };
-} // namespace extractor
 } // namespace osrm
 
 #endif // GEOMETRY_COMPRESSOR_HPP_
diff --git a/include/extractor/compressed_node_based_graph_edge.hpp b/include/extractor/compressed_node_based_graph_edge.hpp
index 279be7c1c..fe840dc0f 100644
--- a/include/extractor/compressed_node_based_graph_edge.hpp
+++ b/include/extractor/compressed_node_based_graph_edge.hpp
@@ -3,9 +3,7 @@
 
 #include "util/typedefs.hpp"
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 // We encode the cnbg graph only using its topology as edge list
@@ -14,7 +12,6 @@ struct CompressedNodeBasedGraphEdge
     NodeID source;
     NodeID target;
 };
-} // namespace extractor
 } // namespace osrm
 
 #endif // OSRM_EXTRACTOR_COMPRESSED_NODE_BASED_GRAPH_EDGE_HPP
diff --git a/include/extractor/conditional_turn_penalty.hpp b/include/extractor/conditional_turn_penalty.hpp
index ef47cbbd8..95facbb01 100644
--- a/include/extractor/conditional_turn_penalty.hpp
+++ b/include/extractor/conditional_turn_penalty.hpp
@@ -8,10 +8,7 @@
 
 #include <type_traits>
 
-namespace osrm
-
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 struct ConditionalTurnPenalty
@@ -22,7 +19,6 @@ struct ConditionalTurnPenalty
     std::vector<util::OpeningHours> conditions;
 };
 
-} // namespace extractor
 } // namespace osrm
 
 #endif // OSRM_EXTRACTOR_CONDITIONAL_TURN_PENALTY_HPP_
diff --git a/include/extractor/datasources.hpp b/include/extractor/datasources.hpp
index ded71b611..c4aa41988 100644
--- a/include/extractor/datasources.hpp
+++ b/include/extractor/datasources.hpp
@@ -8,9 +8,7 @@
 #include <cstdint>
 #include <string_view>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 class Datasources
@@ -45,7 +43,6 @@ class Datasources
     std::array<std::uint32_t, MAX_NUM_SOURES> lengths;
     std::array<char, MAX_LENGTH_NAME * MAX_NUM_SOURES> sources;
 };
-} // namespace extractor
 } // namespace osrm
 
 #endif
diff --git a/include/extractor/edge_based_edge.hpp b/include/extractor/edge_based_edge.hpp
index 781db7af8..95af597c7 100644
--- a/include/extractor/edge_based_edge.hpp
+++ b/include/extractor/edge_based_edge.hpp
@@ -5,9 +5,7 @@
 #include "util/typedefs.hpp"
 #include <tuple>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 struct EdgeBasedEdge
@@ -96,7 +94,6 @@ inline bool EdgeBasedEdge::operator<(const EdgeBasedEdge &other) const
     return std::tie(source, target, data.weight, unidirectional) <
            std::tie(other.source, other.target, other.data.weight, other_is_unidirectional);
 }
-} // namespace extractor
 } // namespace osrm
 
 #endif /* EDGE_BASED_EDGE_HPP */
diff --git a/include/extractor/edge_based_graph_factory.hpp b/include/extractor/edge_based_graph_factory.hpp
index 2aee50c1f..009896a9c 100644
--- a/include/extractor/edge_based_graph_factory.hpp
+++ b/include/extractor/edge_based_graph_factory.hpp
@@ -36,9 +36,7 @@
 #include <unordered_set>
 #include <vector>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 class ScriptingEnvironment;
@@ -173,7 +171,6 @@ class EdgeBasedGraphFactory
     // mapping of node-based edges to edge-based nodes
     std::vector<NodeID> nbe_to_ebn_mapping;
 };
-} // namespace extractor
 } // namespace osrm
 
 #endif /* EDGE_BASED_GRAPH_FACTORY_HPP_ */
diff --git a/include/extractor/edge_based_node.hpp b/include/extractor/edge_based_node.hpp
index d96a39731..6fbab52fb 100644
--- a/include/extractor/edge_based_node.hpp
+++ b/include/extractor/edge_based_node.hpp
@@ -3,9 +3,7 @@
 
 #include "util/typedefs.hpp"
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 struct EdgeBasedNode
@@ -16,7 +14,6 @@ struct EdgeBasedNode
     std::uint32_t segregated : 1;
 };
 
-} // namespace extractor
 } // namespace osrm
 
 #endif // OSRM_EXTRACTOR_EDGE_BASED_NODE_HPP_
diff --git a/include/extractor/edge_based_node_segment.hpp b/include/extractor/edge_based_node_segment.hpp
index ff2198803..f16571eab 100644
--- a/include/extractor/edge_based_node_segment.hpp
+++ b/include/extractor/edge_based_node_segment.hpp
@@ -10,9 +10,7 @@
 
 #include <limits>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 /// This is what util::StaticRTree serialized and stores on disk
@@ -48,7 +46,6 @@ struct EdgeBasedNodeSegment
     unsigned short fwd_segment_position : 15; // segment id in a compressed geometry
     bool is_startpoint : 1;
 };
-} // namespace extractor
 } // namespace osrm
 
 #endif // OSRM_EXTRACT_EDGE_BASED_NODE_SEGMENT_HPP
diff --git a/include/extractor/extraction_containers.hpp b/include/extractor/extraction_containers.hpp
index 6f643aed0..746ebb38b 100644
--- a/include/extractor/extraction_containers.hpp
+++ b/include/extractor/extraction_containers.hpp
@@ -14,9 +14,7 @@
 #include <unordered_map>
 #include <unordered_set>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 /**
@@ -91,7 +89,6 @@ class ExtractionContainers
     void PrepareData(ScriptingEnvironment &scripting_environment,
                      const std::string &names_data_path);
 };
-} // namespace extractor
 } // namespace osrm
 
 #endif /* EXTRACTION_CONTAINERS_HPP */
diff --git a/include/extractor/extraction_helper_functions.hpp b/include/extractor/extraction_helper_functions.hpp
index d9e0f9b44..bb59c3257 100644
--- a/include/extractor/extraction_helper_functions.hpp
+++ b/include/extractor/extraction_helper_functions.hpp
@@ -14,9 +14,7 @@
 
 #include "guidance/parsing_toolkit.hpp"
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 namespace detail
@@ -136,7 +134,6 @@ inline std::string canonicalizeStringList(std::string strlist, const std::string
     return strlist;
 }
 
-} // namespace extractor
 } // namespace osrm
 
 #endif // EXTRACTION_HELPER_FUNCTIONS_HPP
diff --git a/include/extractor/extraction_node.hpp b/include/extractor/extraction_node.hpp
index 9a146d4d3..1203fb1df 100644
--- a/include/extractor/extraction_node.hpp
+++ b/include/extractor/extraction_node.hpp
@@ -3,9 +3,7 @@
 
 #include "traffic_lights.hpp"
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 struct ExtractionNode
@@ -19,7 +17,6 @@ struct ExtractionNode
     TrafficLightClass::Direction traffic_lights;
     bool barrier;
 };
-} // namespace extractor
 } // namespace osrm
 
 #endif // EXTRACTION_NODE_HPP
diff --git a/include/extractor/extraction_relation.hpp b/include/extractor/extraction_relation.hpp
index 6c4203b75..cee830c8a 100644
--- a/include/extractor/extraction_relation.hpp
+++ b/include/extractor/extraction_relation.hpp
@@ -11,9 +11,7 @@
 #include <unordered_map>
 #include <vector>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 struct ExtractionRelation
@@ -199,7 +197,6 @@ class ExtractionRelationContainer
     RelationRefMap rel_refs;
 };
 
-} // namespace extractor
 } // namespace osrm
 
 #endif // EXTRACTION_RELATION_HPP
diff --git a/include/extractor/extraction_segment.hpp b/include/extractor/extraction_segment.hpp
index 4330e5c99..3f009cc22 100644
--- a/include/extractor/extraction_segment.hpp
+++ b/include/extractor/extraction_segment.hpp
@@ -3,9 +3,7 @@
 
 #include <util/coordinate.hpp>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 struct ExtractionSegment
@@ -26,7 +24,6 @@ struct ExtractionSegment
     double weight;
     double duration;
 };
-} // namespace extractor
 } // namespace osrm
 
 #endif
diff --git a/include/extractor/extraction_turn.hpp b/include/extractor/extraction_turn.hpp
index a3026bd5c..809dcc5d2 100644
--- a/include/extractor/extraction_turn.hpp
+++ b/include/extractor/extraction_turn.hpp
@@ -9,9 +9,7 @@
 #include <cstdint>
 #include <vector>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 struct ExtractionTurnLeg
@@ -131,7 +129,6 @@ struct ExtractionTurn
     double weight;
     double duration;
 };
-} // namespace extractor
 } // namespace osrm
 
 #endif
diff --git a/include/extractor/extraction_way.hpp b/include/extractor/extraction_way.hpp
index 674555c81..5c295fade 100644
--- a/include/extractor/extraction_way.hpp
+++ b/include/extractor/extraction_way.hpp
@@ -9,9 +9,7 @@
 #include <string>
 #include <vector>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 namespace detail
 {
@@ -130,7 +128,6 @@ struct ExtractionWay
     std::uint8_t highway_turn_classification : 4;
     std::uint8_t access_turn_classification : 4;
 };
-} // namespace extractor
 } // namespace osrm
 
 #endif // EXTRACTION_WAY_HPP
diff --git a/include/extractor/extractor.hpp b/include/extractor/extractor.hpp
index fb32af8a0..1e840776c 100644
--- a/include/extractor/extractor.hpp
+++ b/include/extractor/extractor.hpp
@@ -46,9 +46,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include "traffic_signals.hpp"
 #include "util/typedefs.hpp"
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 class ScriptingEnvironment;
@@ -120,7 +118,6 @@ class Extractor
                               LaneDescriptionMap lane_description_map,
                               ScriptingEnvironment &scripting_environment);
 };
-} // namespace extractor
 } // namespace osrm
 
 #endif /* EXTRACTOR_HPP */
diff --git a/include/extractor/extractor_callbacks.hpp b/include/extractor/extractor_callbacks.hpp
index 9939a4963..c4ecef952 100644
--- a/include/extractor/extractor_callbacks.hpp
+++ b/include/extractor/extractor_callbacks.hpp
@@ -37,9 +37,7 @@ template <> struct hash<std::tuple<std::string, std::string, std::string, std::s
 };
 } // namespace std
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 class ExtractionContainers;
@@ -95,7 +93,6 @@ class ExtractorCallbacks
     // warning: caller needs to take care of synchronization!
     void ProcessManeuverOverride(const InputManeuverOverride &override);
 };
-} // namespace extractor
 } // namespace osrm
 
 #endif /* EXTRACTOR_CALLBACKS_HPP */
diff --git a/include/extractor/extractor_config.hpp b/include/extractor/extractor_config.hpp
index f25e3ebfc..215a86337 100644
--- a/include/extractor/extractor_config.hpp
+++ b/include/extractor/extractor_config.hpp
@@ -35,9 +35,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include "storage/io_config.hpp"
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 struct ExtractorConfig final : storage::IOConfig
@@ -91,7 +89,6 @@ struct ExtractorConfig final : storage::IOConfig
     bool use_locations_cache = true;
     bool dump_nbg_graph = false;
 };
-} // namespace extractor
 } // namespace osrm
 
 #endif // EXTRACTOR_CONFIG_HPP
diff --git a/include/extractor/files.hpp b/include/extractor/files.hpp
index 8cd4f1e95..843bdeee9 100644
--- a/include/extractor/files.hpp
+++ b/include/extractor/files.hpp
@@ -18,11 +18,7 @@
 
 #include <boost/assert.hpp>
 
-namespace osrm
-{
-namespace extractor
-{
-namespace files
+namespace osrm::extractor::files
 {
 
 // writes the .osrm.icd file
@@ -578,8 +574,6 @@ void readCompressedNodeBasedGraph(const boost::filesystem::path &path, EdgeListT
 
     storage::serialization::read(reader, "/extractor/cnbg", edge_list);
 }
-} // namespace files
-} // namespace extractor
 } // namespace osrm
 
 #endif
diff --git a/include/extractor/graph_compressor.hpp b/include/extractor/graph_compressor.hpp
index 1b6d8159a..e5aaef90a 100644
--- a/include/extractor/graph_compressor.hpp
+++ b/include/extractor/graph_compressor.hpp
@@ -11,9 +11,7 @@
 #include <unordered_set>
 #include <vector>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 class CompressedEdgeContainer;
@@ -39,7 +37,6 @@ class GraphCompressor
                          unsigned original_number_of_edges,
                          const util::NodeBasedDynamicGraph &graph) const;
 };
-} // namespace extractor
 } // namespace osrm
 
 #endif
diff --git a/include/extractor/internal_extractor_edge.hpp b/include/extractor/internal_extractor_edge.hpp
index 11c52b743..6dc87f240 100644
--- a/include/extractor/internal_extractor_edge.hpp
+++ b/include/extractor/internal_extractor_edge.hpp
@@ -10,9 +10,7 @@
 #include <mapbox/variant.hpp>
 #include <utility>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 namespace detail
@@ -86,7 +84,6 @@ struct InternalExtractorEdge
     // coordinate of the source node
     util::Coordinate source_coordinate;
 };
-} // namespace extractor
 } // namespace osrm
 
 #endif // INTERNAL_EXTRACTOR_EDGE_HPP
diff --git a/include/extractor/intersection/constants.hpp b/include/extractor/intersection/constants.hpp
index 6fa6501ae..69d2b9579 100644
--- a/include/extractor/intersection/constants.hpp
+++ b/include/extractor/intersection/constants.hpp
@@ -1,11 +1,7 @@
 #ifndef OSRM_EXTRACTOR_INTERSECTION_CONSTANTS_HPP_
 #define OSRM_EXTRACTOR_INTERSECTION_CONSTANTS_HPP_
 
-namespace osrm
-{
-namespace extractor
-{
-namespace intersection
+namespace osrm::extractor::intersection
 {
 
 // what angle is interpreted as going straight
@@ -30,8 +26,6 @@ const auto constexpr ASSUMED_LANE_WIDTH = 3.25;
 // how far apart can roads be at the most, when thinking about merging them?
 const auto constexpr MERGABLE_ANGLE_DIFFERENCE = 95.0;
 
-} // namespace intersection
-} // namespace extractor
 } // namespace osrm
 
 #endif // OSRM_EXTRACTOR_INTERSECTION_CONSTANTS_HPP_
diff --git a/include/extractor/intersection/coordinate_extractor.hpp b/include/extractor/intersection/coordinate_extractor.hpp
index 4e9999af1..c50555cac 100644
--- a/include/extractor/intersection/coordinate_extractor.hpp
+++ b/include/extractor/intersection/coordinate_extractor.hpp
@@ -11,11 +11,7 @@
 #include "util/coordinate.hpp"
 #include "util/node_based_graph.hpp"
 
-namespace osrm
-{
-namespace extractor
-{
-namespace intersection
+namespace osrm::extractor::intersection
 {
 
 class CoordinateExtractor
@@ -251,8 +247,6 @@ class CoordinateExtractor
                         const std::uint8_t considered_lanes) const;
 };
 
-} // namespace intersection
-} // namespace extractor
 } // namespace osrm
 
 #endif // OSRM_EXTRACTOR_INTERSECTION_COORDINATE_EXTRACTOR_HPP_
diff --git a/include/extractor/intersection/have_identical_names.hpp b/include/extractor/intersection/have_identical_names.hpp
index 72168d829..79a49d6e5 100644
--- a/include/extractor/intersection/have_identical_names.hpp
+++ b/include/extractor/intersection/have_identical_names.hpp
@@ -5,11 +5,7 @@
 #include "extractor/suffix_table.hpp"
 #include "guidance/constants.hpp"
 
-namespace osrm
-{
-namespace extractor
-{
-namespace intersection
+namespace osrm::extractor::intersection
 {
 
 // check if two name ids can be seen as identical (in presence of refs/others)
@@ -20,8 +16,6 @@ bool HaveIdenticalNames(const NameID lhs,
                         const NameTable &name_table,
                         const SuffixTable &street_name_suffix_table);
 
-} // namespace intersection
-} // namespace extractor
 } // namespace osrm
 
 #endif /*OSRM_EXTRACTOR_INTERSECTION_HAVE_IDENTICAL_NAMES_HPP_*/
diff --git a/include/extractor/intersection/intersection_analysis.hpp b/include/extractor/intersection/intersection_analysis.hpp
index aa4a1e939..dc967b26b 100644
--- a/include/extractor/intersection/intersection_analysis.hpp
+++ b/include/extractor/intersection/intersection_analysis.hpp
@@ -14,11 +14,7 @@
 #include <unordered_set>
 #include <vector>
 
-namespace osrm
-{
-namespace extractor
-{
-namespace intersection
+namespace osrm::extractor::intersection
 {
 
 IntersectionEdges getIncomingEdges(const util::NodeBasedDynamicGraph &graph,
@@ -89,8 +85,6 @@ getConnectedRoadsForEdgeGeometries(const util::NodeBasedDynamicGraph &graph,
 // for getConnectedRoads.
 IntersectionEdge skipDegreeTwoNodes(const util::NodeBasedDynamicGraph &graph,
                                     IntersectionEdge road);
-} // namespace intersection
-} // namespace extractor
 } // namespace osrm
 
 #endif
diff --git a/include/extractor/intersection/intersection_edge.hpp b/include/extractor/intersection/intersection_edge.hpp
index fcf5bc5d4..a0fab3144 100644
--- a/include/extractor/intersection/intersection_edge.hpp
+++ b/include/extractor/intersection/intersection_edge.hpp
@@ -5,11 +5,7 @@
 
 #include <vector>
 
-namespace osrm
-{
-namespace extractor
-{
-namespace intersection
+namespace osrm::extractor::intersection
 {
 
 // IntersectionEdge is an alias for incoming and outgoing node-based graph edges of an intersection
@@ -42,8 +38,6 @@ struct IntersectionEdgeGeometry
 };
 
 using IntersectionEdgeGeometries = std::vector<IntersectionEdgeGeometry>;
-} // namespace intersection
-} // namespace extractor
 } // namespace osrm
 
 #endif
diff --git a/include/extractor/intersection/intersection_view.hpp b/include/extractor/intersection/intersection_view.hpp
index 24996bca9..d38b5159a 100644
--- a/include/extractor/intersection/intersection_view.hpp
+++ b/include/extractor/intersection/intersection_view.hpp
@@ -21,11 +21,7 @@
 #include <type_traits>
 #include <vector>
 
-namespace osrm
-{
-namespace extractor
-{
-namespace intersection
+namespace osrm::extractor::intersection
 {
 
 inline auto makeCompareAngularDeviation(const double angle)
@@ -232,8 +228,6 @@ struct IntersectionView final : std::vector<IntersectionViewData>,      //
     using Base = std::vector<IntersectionViewData>;
 };
 
-} // namespace intersection
-} // namespace extractor
 } // namespace osrm
 
 #endif /* OSRM_EXTRACTOR_INTERSECTION_INTERSECTION_VIEW_HPP_*/
diff --git a/include/extractor/intersection/node_based_graph_walker.hpp b/include/extractor/intersection/node_based_graph_walker.hpp
index d076e5e43..45755ea62 100644
--- a/include/extractor/intersection/node_based_graph_walker.hpp
+++ b/include/extractor/intersection/node_based_graph_walker.hpp
@@ -15,11 +15,7 @@
 #include <cstdint>
 #include <utility>
 
-namespace osrm
-{
-namespace extractor
-{
-namespace intersection
+namespace osrm::extractor::intersection
 {
 
 /*
@@ -311,8 +307,6 @@ struct DistanceToNextIntersectionAccumulator
     double distance = 0.;
 };
 
-} // namespace intersection
-} // namespace extractor
 } // namespace osrm
 
 #endif
diff --git a/include/extractor/intersection_bearings_container.hpp b/include/extractor/intersection_bearings_container.hpp
index 7c6d025d2..47fcbfeef 100644
--- a/include/extractor/intersection_bearings_container.hpp
+++ b/include/extractor/intersection_bearings_container.hpp
@@ -10,9 +10,7 @@
 
 #include <numeric>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 namespace detail
 {
@@ -106,7 +104,6 @@ template <storage::Ownership Ownership> class IntersectionBearingsContainer
 using IntersectionBearingsContainer =
     detail::IntersectionBearingsContainer<storage::Ownership::Container>;
 using IntersectionBearingsView = detail::IntersectionBearingsContainer<storage::Ownership::View>;
-} // namespace extractor
 } // namespace osrm
 
 #endif
diff --git a/include/extractor/location_dependent_data.hpp b/include/extractor/location_dependent_data.hpp
index afb0a66b9..26b68d163 100644
--- a/include/extractor/location_dependent_data.hpp
+++ b/include/extractor/location_dependent_data.hpp
@@ -11,9 +11,7 @@
 #include <string>
 #include <unordered_map>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 struct LocationDependentData
@@ -48,7 +46,6 @@ struct LocationDependentData
     std::vector<std::pair<polygon_bands_t, std::size_t>> polygons;
     std::vector<properties_t> properties;
 };
-} // namespace extractor
 } // namespace osrm
 
 #endif
diff --git a/include/extractor/maneuver_override.hpp b/include/extractor/maneuver_override.hpp
index f23c3e928..1d73bae49 100644
--- a/include/extractor/maneuver_override.hpp
+++ b/include/extractor/maneuver_override.hpp
@@ -13,9 +13,7 @@
 #include <boost/functional/hash.hpp>
 #include <mapbox/variant.hpp>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 // Data that is loaded from the OSM datafile directly
@@ -143,7 +141,6 @@ struct UnresolvedManeuverOverride
 
     static std::string Name() { return "maneuver override"; };
 };
-} // namespace extractor
 } // namespace osrm
 
 // custom specialization of std::hash can be injected in namespace std
diff --git a/include/extractor/maneuver_override_relation_parser.hpp b/include/extractor/maneuver_override_relation_parser.hpp
index 31355fcb2..259d61297 100644
--- a/include/extractor/maneuver_override_relation_parser.hpp
+++ b/include/extractor/maneuver_override_relation_parser.hpp
@@ -12,9 +12,7 @@ namespace osmium
 class Relation;
 } // namespace osmium
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 class ScriptingEnvironment;
@@ -59,7 +57,6 @@ class ManeuverOverrideRelationParser
     ManeuverOverrideRelationParser();
     boost::optional<InputManeuverOverride> TryParse(const osmium::Relation &relation) const;
 };
-} // namespace extractor
 } // namespace osrm
 
 #endif /* RESTRICTION_PARSER_HPP */
diff --git a/include/extractor/name_table.hpp b/include/extractor/name_table.hpp
index 44cc06f89..94f84aa00 100644
--- a/include/extractor/name_table.hpp
+++ b/include/extractor/name_table.hpp
@@ -7,9 +7,7 @@
 #include <string>
 #include <string_view>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 namespace detail
@@ -115,7 +113,6 @@ template <storage::Ownership Ownership> class NameTableImpl
 
 using NameTable = detail::NameTableImpl<storage::Ownership::Container>;
 using NameTableView = detail::NameTableImpl<storage::Ownership::View>;
-} // namespace extractor
 } // namespace osrm
 
 #endif // OSRM_EXTRACTOR_NAME_TABLE_HPP
diff --git a/include/extractor/nbg_to_ebg.hpp b/include/extractor/nbg_to_ebg.hpp
index 6859db9a8..18a0d9f8e 100644
--- a/include/extractor/nbg_to_ebg.hpp
+++ b/include/extractor/nbg_to_ebg.hpp
@@ -3,9 +3,7 @@
 
 #include "util/typedefs.hpp"
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 // Mapping betweenn the node based graph u,v nodes and the edge based graph head,tail edge ids.
@@ -15,7 +13,6 @@ struct NBGToEBG
     NodeID u, v;
     NodeID forward_ebg_node, backward_ebg_node;
 };
-} // namespace extractor
 } // namespace osrm
 
 #endif
diff --git a/include/extractor/node_based_edge.hpp b/include/extractor/node_based_edge.hpp
index 5c97b3e67..f5aacd569 100644
--- a/include/extractor/node_based_edge.hpp
+++ b/include/extractor/node_based_edge.hpp
@@ -10,9 +10,7 @@
 
 #include "extractor/road_classification.hpp"
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 // Flags describing the class of the road. This data is used during creation of graphs/guidance
@@ -207,7 +205,6 @@ static_assert(sizeof(extractor::NodeBasedEdge) == 32,
               "bigger than expected. This will influence "
               "memory consumption.");
 
-} // namespace extractor
 } // namespace osrm
 
 #endif /* NODE_BASED_EDGE_HPP */
diff --git a/include/extractor/node_based_graph_factory.hpp b/include/extractor/node_based_graph_factory.hpp
index 7c0a70f2e..20765260d 100644
--- a/include/extractor/node_based_graph_factory.hpp
+++ b/include/extractor/node_based_graph_factory.hpp
@@ -19,9 +19,7 @@
 #include <unordered_set>
 #include <vector>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 // Turn the output of the extraction process into a graph that represents junctions as nodes and
@@ -104,7 +102,6 @@ class NodeBasedGraphFactory
     extractor::CompressedEdgeContainer compressed_edge_container;
 };
 
-} // namespace extractor
 } // namespace osrm
 
 #endif // OSRM_EXTRACTOR_NODE_BASED_GRAPH_FACTORY_HPP_
diff --git a/include/extractor/node_data_container.hpp b/include/extractor/node_data_container.hpp
index b3825c314..6c596e86c 100644
--- a/include/extractor/node_data_container.hpp
+++ b/include/extractor/node_data_container.hpp
@@ -13,9 +13,7 @@
 #include "util/typedefs.hpp"
 #include "util/vector_view.hpp"
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 class Extractor;
@@ -129,7 +127,6 @@ using EdgeBasedNodeDataExternalContainer =
 using EdgeBasedNodeDataContainer =
     detail::EdgeBasedNodeDataContainerImpl<storage::Ownership::Container>;
 using EdgeBasedNodeDataView = detail::EdgeBasedNodeDataContainerImpl<storage::Ownership::View>;
-} // namespace extractor
 } // namespace osrm
 
 #endif
diff --git a/include/extractor/node_restriction_map.hpp b/include/extractor/node_restriction_map.hpp
index fe7e89673..181e4ab00 100644
--- a/include/extractor/node_restriction_map.hpp
+++ b/include/extractor/node_restriction_map.hpp
@@ -11,9 +11,7 @@
 #include <utility>
 #include <vector>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 // Allows easy check for whether a node restriction is present at a given intersection
@@ -74,7 +72,6 @@ struct UnconditionalOnly
 using RestrictionMap = NodeRestrictionMap<UnconditionalOnly>;
 using ConditionalRestrictionMap = NodeRestrictionMap<ConditionalOnly>;
 
-} // namespace extractor
 } // namespace osrm
 
 #endif // OSRM_EXTRACTOR_NODE_RESTRICTION_MAP_HPP_
diff --git a/include/extractor/nodes_of_way.hpp b/include/extractor/nodes_of_way.hpp
index d7f19c705..26a2ac38a 100644
--- a/include/extractor/nodes_of_way.hpp
+++ b/include/extractor/nodes_of_way.hpp
@@ -7,9 +7,7 @@
 #include <string>
 #include <vector>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 // NodesOfWay contains the ordered nodes of a way and provides convenience functions for getting
@@ -50,7 +48,6 @@ struct NodesOfWay
         return node_ids[node_ids.size() - 1];
     }
 };
-} // namespace extractor
 } // namespace osrm
 
 #endif /* NODES_OF_WAY_HPP */
diff --git a/include/extractor/packed_osm_ids.hpp b/include/extractor/packed_osm_ids.hpp
index 137c2f67a..845a190fc 100644
--- a/include/extractor/packed_osm_ids.hpp
+++ b/include/extractor/packed_osm_ids.hpp
@@ -4,9 +4,7 @@
 #include "util/packed_vector.hpp"
 #include "util/typedefs.hpp"
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 namespace detail
 {
@@ -16,7 +14,6 @@ using PackedOSMIDs = util::detail::PackedVector<OSMNodeID, 34, Ownership>;
 
 using PackedOSMIDsView = detail::PackedOSMIDs<storage::Ownership::View>;
 using PackedOSMIDs = detail::PackedOSMIDs<storage::Ownership::Container>;
-} // namespace extractor
 } // namespace osrm
 
 #endif
diff --git a/include/extractor/profile_properties.hpp b/include/extractor/profile_properties.hpp
index 953c5be1b..80154333b 100644
--- a/include/extractor/profile_properties.hpp
+++ b/include/extractor/profile_properties.hpp
@@ -13,9 +13,7 @@
 #include <array>
 #include <cstdint>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 const constexpr auto DEFAULT_MAX_SPEED = 180 / 3.6; // 180kmph -> m/s
@@ -138,7 +136,6 @@ struct ProfileProperties
     bool force_split_edges = false;
     bool call_tagless_node_function = true;
 };
-} // namespace extractor
 } // namespace osrm
 
 #endif
diff --git a/include/extractor/query_node.hpp b/include/extractor/query_node.hpp
index 557c80eea..b3723ea10 100644
--- a/include/extractor/query_node.hpp
+++ b/include/extractor/query_node.hpp
@@ -8,9 +8,7 @@
 #include <cstdint>
 #include <limits>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 struct QueryNode
@@ -48,7 +46,6 @@ struct QueryNode
                          MAX_OSM_NODEID);
     }
 };
-} // namespace extractor
 } // namespace osrm
 
 #endif // QUERY_NODE_HPP
diff --git a/include/extractor/raster_source.hpp b/include/extractor/raster_source.hpp
index aa6e2c97b..d70548bfe 100644
--- a/include/extractor/raster_source.hpp
+++ b/include/extractor/raster_source.hpp
@@ -19,9 +19,7 @@
 #include <string>
 #include <unordered_map>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 /**
@@ -173,7 +171,6 @@ class RasterCache
     // the instance
     static RasterCache *g_instance;
 };
-} // namespace extractor
 } // namespace osrm
 
 #endif /* RASTER_SOURCE_HPP */
diff --git a/include/extractor/restriction.hpp b/include/extractor/restriction.hpp
index c00fd20a4..b05db4f1e 100644
--- a/include/extractor/restriction.hpp
+++ b/include/extractor/restriction.hpp
@@ -9,9 +9,7 @@
 #include "turn_path.hpp"
 #include <limits>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 // External (OSM) representation of restriction
@@ -63,7 +61,6 @@ struct TurnRestriction
 
     static std::string Name() { return "turn restriction"; };
 };
-} // namespace extractor
 } // namespace osrm
 
 #endif // RESTRICTION_HPP
diff --git a/include/extractor/restriction_graph.hpp b/include/extractor/restriction_graph.hpp
index 15932720c..301d1f141 100644
--- a/include/extractor/restriction_graph.hpp
+++ b/include/extractor/restriction_graph.hpp
@@ -9,9 +9,7 @@
 
 #include <unordered_map>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 struct TurnRestriction;
@@ -131,7 +129,6 @@ struct RestrictionGraph
 
 RestrictionGraph constructRestrictionGraph(const std::vector<TurnRestriction> &turn_restrictions);
 
-} // namespace extractor
 } // namespace osrm
 
 #endif // OSRM_EXTRACTOR_RESTRICTION_GRAPH_HPP_
diff --git a/include/extractor/restriction_parser.hpp b/include/extractor/restriction_parser.hpp
index 869ff9b84..ccf8303a4 100644
--- a/include/extractor/restriction_parser.hpp
+++ b/include/extractor/restriction_parser.hpp
@@ -15,9 +15,7 @@ namespace osmium
 class Relation;
 } // namespace osmium
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 class ScriptingEnvironment;
@@ -56,7 +54,6 @@ class RestrictionParser
     std::set<std::string> restrictions;
     osmium::tags::KeyFilter filter;
 };
-} // namespace extractor
 } // namespace osrm
 
 #endif /* RESTRICTION_PARSER_HPP */
diff --git a/include/extractor/road_classification.hpp b/include/extractor/road_classification.hpp
index 850c6363c..07aa11738 100644
--- a/include/extractor/road_classification.hpp
+++ b/include/extractor/road_classification.hpp
@@ -9,9 +9,7 @@
 #include <cstdlib>
 #include <string>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 // Priorities are used to distinguish between how likely a turn is in comparison to a different
@@ -223,7 +221,6 @@ inline bool obviousByRoadClass(const RoadClassification in_classification,
             compare_candidate.IsLowPriorityRoadClass());
 }
 
-} // namespace extractor
 } // namespace osrm
 
 #endif // OSRM_EXTRACTOR_CLASSIFICATION_DATA_HPP_
diff --git a/include/extractor/scripting_environment_lua.hpp b/include/extractor/scripting_environment_lua.hpp
index f3ac12f95..a89d2a1b8 100644
--- a/include/extractor/scripting_environment_lua.hpp
+++ b/include/extractor/scripting_environment_lua.hpp
@@ -14,9 +14,7 @@
 
 #include <sol/sol.hpp>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 struct LuaScriptingContext final
@@ -110,7 +108,6 @@ class Sol2ScriptingEnvironment final : public ScriptingEnvironment
     tbb::enumerable_thread_specific<std::unique_ptr<LuaScriptingContext>> script_contexts;
     const LocationDependentData location_dependent_data;
 };
-} // namespace extractor
 } // namespace osrm
 
 #endif /* SCRIPTING_ENVIRONMENT_LUA_HPP */
diff --git a/include/extractor/segment_data_container.hpp b/include/extractor/segment_data_container.hpp
index 700455047..f7baf2f5c 100644
--- a/include/extractor/segment_data_container.hpp
+++ b/include/extractor/segment_data_container.hpp
@@ -17,9 +17,7 @@
 #include <string>
 #include <vector>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 class CompressedEdgeContainer;
@@ -225,7 +223,6 @@ template <storage::Ownership Ownership> class SegmentDataContainerImpl
 
 using SegmentDataView = detail::SegmentDataContainerImpl<storage::Ownership::View>;
 using SegmentDataContainer = detail::SegmentDataContainerImpl<storage::Ownership::Container>;
-} // namespace extractor
 } // namespace osrm
 
 #endif
diff --git a/include/extractor/serialization.hpp b/include/extractor/serialization.hpp
index e0e0127b2..4db02de5a 100644
--- a/include/extractor/serialization.hpp
+++ b/include/extractor/serialization.hpp
@@ -17,11 +17,7 @@
 
 #include <boost/assert.hpp>
 
-namespace osrm
-{
-namespace extractor
-{
-namespace serialization
+namespace osrm::extractor::serialization
 {
 
 // read/write for bearing data
@@ -222,8 +218,6 @@ inline void read(storage::tar::FileReader &reader,
     std::string buffer;
     util::serialization::read(reader, name, name_table.indexed_data);
 }
-} // namespace serialization
-} // namespace extractor
 } // namespace osrm
 
 #endif
diff --git a/include/extractor/suffix_table.hpp b/include/extractor/suffix_table.hpp
index cadfb5e2e..1d26fcef6 100644
--- a/include/extractor/suffix_table.hpp
+++ b/include/extractor/suffix_table.hpp
@@ -6,9 +6,7 @@
 #include <unordered_set>
 #include <vector>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 class ScriptingEnvironment;
@@ -39,7 +37,6 @@ class SuffixTable final
     std::unordered_set<std::string_view> suffix_set;
 };
 
-} /* namespace extractor */
 } /* namespace osrm */
 
 #endif /* OSRM_EXTRACTOR_SUFFIX_LIST_HPP_ */
diff --git a/include/extractor/tarjan_scc.hpp b/include/extractor/tarjan_scc.hpp
index c4ccac1ca..2b4fdc23b 100644
--- a/include/extractor/tarjan_scc.hpp
+++ b/include/extractor/tarjan_scc.hpp
@@ -22,9 +22,7 @@
 #include <stack>
 #include <vector>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 template <typename GraphT> class TarjanSCC
@@ -180,7 +178,6 @@ template <typename GraphT> class TarjanSCC
 
     unsigned GetComponentID(const NodeID node) const { return components_index[node]; }
 };
-} // namespace extractor
 } // namespace osrm
 
 #endif /* TARJAN_SCC_HPP */
diff --git a/include/extractor/traffic_lights.hpp b/include/extractor/traffic_lights.hpp
index 0c8aa6d00..b4250e173 100644
--- a/include/extractor/traffic_lights.hpp
+++ b/include/extractor/traffic_lights.hpp
@@ -1,12 +1,7 @@
 #ifndef OSRM_EXTRACTOR_TRAFFIC_LIGHTS_DATA_HPP_
 #define OSRM_EXTRACTOR_TRAFFIC_LIGHTS_DATA_HPP_
 
-namespace osrm
-{
-namespace extractor
-{
-
-namespace TrafficLightClass
+namespace osrm::extractor::TrafficLightClass
 {
 // The traffic light annotation is extracted from node tags.
 // The directions in which the traffic light applies are relative to the way containing the node.
@@ -17,9 +12,6 @@ enum Direction
     DIRECTION_FORWARD = 2,
     DIRECTION_REVERSE = 3
 };
-} // namespace TrafficLightClass
-
-} // namespace extractor
 } // namespace osrm
 
 #endif // OSRM_EXTRACTOR_TRAFFIC_LIGHTS_DATA_HPP_
diff --git a/include/extractor/traffic_signals.hpp b/include/extractor/traffic_signals.hpp
index 8d594c6d9..47ff9c09f 100644
--- a/include/extractor/traffic_signals.hpp
+++ b/include/extractor/traffic_signals.hpp
@@ -6,9 +6,7 @@
 #include <boost/functional/hash.hpp>
 #include <unordered_set>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 struct TrafficSignals
@@ -22,7 +20,6 @@ struct TrafficSignals
         return bidirectional_nodes.count(to) > 0 || unidirectional_segments.count({from, to}) > 0;
     }
 };
-} // namespace extractor
 } // namespace osrm
 
 #endif // OSRM_EXTRACTOR_TRAFFIC_SIGNALS_HPP
diff --git a/include/extractor/travel_mode.hpp b/include/extractor/travel_mode.hpp
index 5ba4bbd1f..82a466ca1 100644
--- a/include/extractor/travel_mode.hpp
+++ b/include/extractor/travel_mode.hpp
@@ -31,9 +31,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <cstdint>
 #include <string>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 // This is a char instead of a typed enum, so that we can
@@ -103,7 +101,6 @@ inline std::string travelModeToString(const TravelMode mode)
     return token;
 }
 
-} // namespace extractor
 } // namespace osrm
 
 #endif /* TRAVEL_MODE_HPP */
diff --git a/include/extractor/turn_lane_types.hpp b/include/extractor/turn_lane_types.hpp
index 73263a79c..a54b9ee16 100644
--- a/include/extractor/turn_lane_types.hpp
+++ b/include/extractor/turn_lane_types.hpp
@@ -13,9 +13,7 @@
 #include <numeric> //partial_sum
 #include <vector>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 namespace TurnLaneType
@@ -100,7 +98,6 @@ inline TurnLanesIndexedArray transformTurnLaneMapIntoArrays(const LaneDescriptio
     return std::make_tuple(std::move(turn_lane_offsets), std::move(turn_lane_masks));
 }
 
-} // namespace extractor
 } // namespace osrm
 
 #endif /* OSRM_GUIDANCE_TURN_LANE_TYPES_HPP_ */
diff --git a/include/extractor/turn_path.hpp b/include/extractor/turn_path.hpp
index 78363f8dd..c562c6c76 100644
--- a/include/extractor/turn_path.hpp
+++ b/include/extractor/turn_path.hpp
@@ -7,9 +7,7 @@
 #include <mapbox/variant.hpp>
 #include <vector>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 // Outside view of the variant, these are equal to the `which()` results
@@ -264,6 +262,5 @@ struct TurnPath
     };
 };
 
-} // namespace extractor
 } // namespace osrm
 #endif // OSRM_TURN_PATH_HPP
diff --git a/include/extractor/turn_path_compressor.hpp b/include/extractor/turn_path_compressor.hpp
index 8f19ea6fa..114590878 100644
--- a/include/extractor/turn_path_compressor.hpp
+++ b/include/extractor/turn_path_compressor.hpp
@@ -6,9 +6,7 @@
 #include <unordered_map>
 #include <vector>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 struct TurnPath;
@@ -48,7 +46,6 @@ class TurnPathCompressor
     std::unordered_multimap<NodeID, TurnPath *> ends;
 };
 
-} // namespace extractor
 } // namespace osrm
 
 #endif // OSRM_EXTRACTOR_TURN_PATH_COMPRESSOR_HPP_
diff --git a/include/extractor/turn_path_filter.hpp b/include/extractor/turn_path_filter.hpp
index 48f32b599..6d8e770fc 100644
--- a/include/extractor/turn_path_filter.hpp
+++ b/include/extractor/turn_path_filter.hpp
@@ -6,9 +6,7 @@
 
 #include <vector>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 // To avoid handling invalid turn paths / creating unnecessary duplicate nodes for via-ways, we do
@@ -16,7 +14,6 @@ namespace extractor
 // `restrictions = removeInvalidRestrictions(std::move(restrictions))`
 template <typename T>
 std::vector<T> removeInvalidTurnPaths(std::vector<T>, const util::NodeBasedDynamicGraph &);
-} // namespace extractor
 } // namespace osrm
 
 #endif // OSRM_EXTRACTOR_TURN_PATH_FILTER_HPP_
diff --git a/include/extractor/way_restriction_map.hpp b/include/extractor/way_restriction_map.hpp
index eb0feaadb..f40db16a5 100644
--- a/include/extractor/way_restriction_map.hpp
+++ b/include/extractor/way_restriction_map.hpp
@@ -11,9 +11,7 @@
 #include <utility>
 #include <vector>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 // Given the compressed representation of via-way turn restrictions, we provide a fast access into
@@ -69,7 +67,6 @@ class WayRestrictionMap
     const RestrictionGraph &restriction_graph;
 };
 
-} // namespace extractor
 } // namespace osrm
 
 #endif // OSRM_EXTRACTOR_WAY_RESTRICTION_MAP_HPP_
diff --git a/include/guidance/constants.hpp b/include/guidance/constants.hpp
index 50745c7a2..780b65297 100644
--- a/include/guidance/constants.hpp
+++ b/include/guidance/constants.hpp
@@ -3,9 +3,7 @@
 
 #include "extractor/intersection/constants.hpp"
 
-namespace osrm
-{
-namespace guidance
+namespace osrm::guidance
 {
 
 // what angle is interpreted as going straight
@@ -30,7 +28,6 @@ const double constexpr INCREASES_BY_FOURTY_PERCENT = 1.4;
 
 const int constexpr MAX_SLIPROAD_THRESHOLD = 250;
 
-} // namespace guidance
 } // namespace osrm
 
 #endif // OSRM_GUIDANCE_CONSTANTS_HPP_
diff --git a/include/guidance/driveway_handler.hpp b/include/guidance/driveway_handler.hpp
index 1ac0d401c..1bdaeb4ab 100644
--- a/include/guidance/driveway_handler.hpp
+++ b/include/guidance/driveway_handler.hpp
@@ -3,9 +3,7 @@
 
 #include "guidance/intersection_handler.hpp"
 
-namespace osrm
-{
-namespace guidance
+namespace osrm::guidance
 {
 
 // Intersection handlers deal with all issues related to intersections.
@@ -35,7 +33,6 @@ class DrivewayHandler final : public IntersectionHandler
                             Intersection intersection) const override final;
 };
 
-} // namespace guidance
 } // namespace osrm
 
 #endif /* OSRM_GUIDANCE_DRIVEWAY_HANDLER_HPP */
diff --git a/include/guidance/files.hpp b/include/guidance/files.hpp
index b57e79987..bd7361d5a 100644
--- a/include/guidance/files.hpp
+++ b/include/guidance/files.hpp
@@ -10,11 +10,7 @@
 
 #include <boost/assert.hpp>
 
-namespace osrm
-{
-namespace guidance
-{
-namespace files
+namespace osrm::guidance::files
 {
 
 // reads .osrm.edges
@@ -51,8 +47,6 @@ inline void writeTurnData(const boost::filesystem::path &path,
     writer.WriteFrom("/common/connectivity_checksum", connectivity_checksum);
     serialization::write(writer, "/common/turn_data", turn_data);
 }
-} // namespace files
-} // namespace guidance
 } // namespace osrm
 
 #endif
diff --git a/include/guidance/guidance_processing.hpp b/include/guidance/guidance_processing.hpp
index 6d2aadf71..2c56dabf5 100644
--- a/include/guidance/guidance_processing.hpp
+++ b/include/guidance/guidance_processing.hpp
@@ -19,9 +19,7 @@
 
 #include <unordered_set>
 
-namespace osrm
-{
-namespace guidance
+namespace osrm::guidance
 {
 using BearingClassesVector = std::vector<BearingClassID>;
 using BearingClassesMap = util::ConcurrentIDMap<util::guidance::BearingClass, BearingClassID>;
@@ -45,7 +43,6 @@ void annotateTurns(const util::NodeBasedDynamicGraph &node_based_graph,
                    EntryClassesMap &entry_class_hash,
                    std::uint32_t &connectivity_checksum);
 
-} // namespace guidance
 } // namespace osrm
 
 #endif
diff --git a/include/guidance/intersection.hpp b/include/guidance/intersection.hpp
index 265febf3c..1f4521c34 100644
--- a/include/guidance/intersection.hpp
+++ b/include/guidance/intersection.hpp
@@ -4,9 +4,7 @@
 #include "extractor/intersection/intersection_view.hpp"
 #include "guidance/turn_instruction.hpp"
 
-namespace osrm
-{
-namespace guidance
+namespace osrm::guidance
 {
 
 // A Connected Road is the internal representation of a potential turn. Internally, we require
@@ -122,7 +120,6 @@ inline std::string toString(const ConnectedRoad &road)
     return result;
 }
 
-} // namespace guidance
 } // namespace osrm
 
 #endif /* OSRM_GUIDANCE_INTERSECTION_HPP_*/
diff --git a/include/guidance/intersection_handler.hpp b/include/guidance/intersection_handler.hpp
index 42221e467..3ba2fb057 100644
--- a/include/guidance/intersection_handler.hpp
+++ b/include/guidance/intersection_handler.hpp
@@ -20,9 +20,7 @@
 
 #include <boost/optional.hpp>
 
-namespace osrm
-{
-namespace guidance
+namespace osrm::guidance
 {
 
 // Intersection handlers deal with all issues related to intersections.
@@ -660,7 +658,6 @@ std::size_t IntersectionHandler::findObviousTurn(const EdgeID via_edge,
     return 0;
 }
 
-} // namespace guidance
 } // namespace osrm
 
 #endif /*OSRM_GUIDANCE_INTERSECTION_HANDLER_HPP_*/
diff --git a/include/guidance/is_through_street.hpp b/include/guidance/is_through_street.hpp
index 15487c50e..53281f196 100644
--- a/include/guidance/is_through_street.hpp
+++ b/include/guidance/is_through_street.hpp
@@ -12,9 +12,7 @@
 
 #include "util/guidance/name_announcements.hpp"
 
-namespace osrm
-{
-namespace guidance
+namespace osrm::guidance
 {
 
 template <typename IntersectionType>
@@ -60,7 +58,6 @@ inline bool isThroughStreet(const std::size_t index,
     return false;
 }
 
-} // namespace guidance
 } // namespace osrm
 
 #endif /*OSRM_GUIDANCE_IS_THROUGH_STREET_HPP_*/
diff --git a/include/guidance/motorway_handler.hpp b/include/guidance/motorway_handler.hpp
index 05f1c1630..630b99e8e 100644
--- a/include/guidance/motorway_handler.hpp
+++ b/include/guidance/motorway_handler.hpp
@@ -12,9 +12,7 @@
 
 #include <vector>
 
-namespace osrm
-{
-namespace guidance
+namespace osrm::guidance
 {
 
 // Intersection handlers deal with all issues related to intersections.
@@ -58,7 +56,6 @@ class MotorwayHandler final : public IntersectionHandler
     Intersection fallback(Intersection intersection) const;
 };
 
-} // namespace guidance
 } // namespace osrm
 
 #endif /*OSRM_GUIDANCE_MOTORWAY_HANDLER_HPP_*/
diff --git a/include/guidance/parsing_toolkit.hpp b/include/guidance/parsing_toolkit.hpp
index 7357265b9..aa3e1e4d1 100644
--- a/include/guidance/parsing_toolkit.hpp
+++ b/include/guidance/parsing_toolkit.hpp
@@ -9,11 +9,7 @@
 
 #include "util/attributes.hpp"
 
-namespace osrm
-{
-namespace extractor
-{
-namespace guidance
+namespace osrm::extractor::guidance
 {
 
 // Public service vehicle lanes and similar can introduce additional lanes into the lane string that
@@ -105,8 +101,6 @@ inline std::string applyAccessTokens(std::string lane_string, const std::string
     return result_string;
 }
 
-} // namespace guidance
-} // namespace extractor
 } // namespace osrm
 
 #endif // OSRM_GUIDANCE_PARSING_TOOLKIT_HPP_
diff --git a/include/guidance/roundabout_handler.hpp b/include/guidance/roundabout_handler.hpp
index 55def24e8..8cab619b0 100644
--- a/include/guidance/roundabout_handler.hpp
+++ b/include/guidance/roundabout_handler.hpp
@@ -17,9 +17,7 @@
 #include <unordered_set>
 #include <vector>
 
-namespace osrm
-{
-namespace guidance
+namespace osrm::guidance
 {
 
 namespace detail
@@ -84,7 +82,6 @@ class RoundaboutHandler final : public IntersectionHandler
     const extractor::intersection::CoordinateExtractor coordinate_extractor;
 };
 
-} // namespace guidance
 } // namespace osrm
 
 #endif /*OSRM_GUIDANCE_ROUNDABOUT_HANDLER_HPP_*/
diff --git a/include/guidance/roundabout_type.hpp b/include/guidance/roundabout_type.hpp
index 3f4eebe8d..daae81e3c 100644
--- a/include/guidance/roundabout_type.hpp
+++ b/include/guidance/roundabout_type.hpp
@@ -1,9 +1,7 @@
 #ifndef OSRM_GUIDANCE_ROUNDABOUT_TYPES_HPP_
 #define OSRM_GUIDANCE_ROUNDABOUT_TYPES_HPP_
 
-namespace osrm
-{
-namespace guidance
+namespace osrm::guidance
 {
 enum class RoundaboutType
 {
@@ -12,7 +10,6 @@ enum class RoundaboutType
     Rotary,                // traffic circle (large roundabout) with dedicated name
     RoundaboutIntersection // small roundabout with distinct turns, handled as intersection
 };
-} /* namespace guidance */
 } /* namespace osrm */
 
 #endif /* OSRM_EXTRACTOR_GUIDANCE_ROUNDABOUT_TYPES_HPP_ */
diff --git a/include/guidance/serialization.hpp b/include/guidance/serialization.hpp
index e5cf544ff..86e196f53 100644
--- a/include/guidance/serialization.hpp
+++ b/include/guidance/serialization.hpp
@@ -8,11 +8,7 @@
 
 #include <boost/assert.hpp>
 
-namespace osrm
-{
-namespace guidance
-{
-namespace serialization
+namespace osrm::guidance::serialization
 {
 
 // read/write for turn data file
@@ -49,8 +45,6 @@ inline void write(storage::tar::FileWriter &writer,
     storage::serialization::write(
         writer, name + "/post_turn_bearings", turn_data_container.post_turn_bearings);
 }
-} // namespace serialization
-} // namespace guidance
 } // namespace osrm
 
 #endif
diff --git a/include/guidance/sliproad_handler.hpp b/include/guidance/sliproad_handler.hpp
index bed9d7424..d88a27e52 100644
--- a/include/guidance/sliproad_handler.hpp
+++ b/include/guidance/sliproad_handler.hpp
@@ -13,9 +13,7 @@
 
 #include <boost/optional.hpp>
 
-namespace osrm
-{
-namespace guidance
+namespace osrm::guidance
 {
 
 // Intersection handlers deal with all issues related to intersections.
@@ -81,7 +79,6 @@ class SliproadHandler final : public IntersectionHandler
     const extractor::intersection::CoordinateExtractor coordinate_extractor;
 };
 
-} // namespace guidance
 } // namespace osrm
 
 #endif /*OSRM_GUIDANCE_SLIPROAD_HANDLER_HPP_*/
diff --git a/include/guidance/statistics_handler.hpp b/include/guidance/statistics_handler.hpp
index 6145228ec..c943eb349 100644
--- a/include/guidance/statistics_handler.hpp
+++ b/include/guidance/statistics_handler.hpp
@@ -15,9 +15,7 @@
 
 #include <cstdint>
 
-namespace osrm
-{
-namespace guidance
+namespace osrm::guidance
 {
 
 // Unconditionally runs over all intersections and gathers statistics for
@@ -107,7 +105,6 @@ class StatisticsHandler final : public IntersectionHandler
     mutable std::map<DirectionModifier::Enum, std::uint64_t> modifier_hist;
 };
 
-} // namespace guidance
 } // namespace osrm
 
 #endif // OSRM_GUIDANCE_VALIDATION_HANDLER_HPP_
diff --git a/include/guidance/suppress_mode_handler.hpp b/include/guidance/suppress_mode_handler.hpp
index bebc79401..6553795fa 100644
--- a/include/guidance/suppress_mode_handler.hpp
+++ b/include/guidance/suppress_mode_handler.hpp
@@ -8,9 +8,7 @@
 
 #include "util/node_based_graph.hpp"
 
-namespace osrm
-{
-namespace guidance
+namespace osrm::guidance
 {
 
 // Suppresses instructions for certain modes.
@@ -40,7 +38,6 @@ class SuppressModeHandler final : public IntersectionHandler
                             Intersection intersection) const override final;
 };
 
-} // namespace guidance
 } // namespace osrm
 
 #endif /* OSRM_GUIDANCE_SUPPRESS_MODE_HANDLER_HPP_ */
diff --git a/include/guidance/turn_analysis.hpp b/include/guidance/turn_analysis.hpp
index 7a97af725..fc2650e60 100644
--- a/include/guidance/turn_analysis.hpp
+++ b/include/guidance/turn_analysis.hpp
@@ -29,9 +29,7 @@
 #include <utility>
 #include <vector>
 
-namespace osrm
-{
-namespace guidance
+namespace osrm::guidance
 {
 
 class TurnAnalysis
@@ -75,7 +73,6 @@ class TurnAnalysis
     setTurnTypes(const NodeID from, const EdgeID via_edge, Intersection intersection) const;
 }; // class TurnAnalysis
 
-} // namespace guidance
 } // namespace osrm
 
 #endif // OSRM_GUIDANCE_TURN_ANALYSIS
diff --git a/include/guidance/turn_bearing.hpp b/include/guidance/turn_bearing.hpp
index 12ba8567c..6165fc0de 100644
--- a/include/guidance/turn_bearing.hpp
+++ b/include/guidance/turn_bearing.hpp
@@ -5,9 +5,7 @@
 
 #include <boost/assert.hpp>
 
-namespace osrm
-{
-namespace guidance
+namespace osrm::guidance
 {
 
 #pragma pack(push, 1)
@@ -29,7 +27,6 @@ class TurnBearing
 };
 #pragma pack(pop)
 
-} // namespace guidance
 } // namespace osrm
 
 #endif /* OSRM_INCLUDE_GUIDANCE_TURN_BEARING_HPP_ */
diff --git a/include/guidance/turn_classification.hpp b/include/guidance/turn_classification.hpp
index 0192d6c99..4103b14a2 100644
--- a/include/guidance/turn_classification.hpp
+++ b/include/guidance/turn_classification.hpp
@@ -9,15 +9,12 @@
 
 #include <utility>
 
-namespace osrm
-{
-namespace guidance
+namespace osrm::guidance
 {
 
 std::pair<util::guidance::EntryClass, util::guidance::BearingClass>
 classifyIntersection(Intersection intersection, const osrm::util::Coordinate &location);
 
-} // namespace guidance
 } // namespace osrm
 
 #endif // OSRM_GUIDANCE_TURN_CLASSIFICATION_HPP_
diff --git a/include/guidance/turn_data_container.hpp b/include/guidance/turn_data_container.hpp
index de52461a2..2500df9a2 100644
--- a/include/guidance/turn_data_container.hpp
+++ b/include/guidance/turn_data_container.hpp
@@ -12,9 +12,7 @@
 
 #include "util/typedefs.hpp"
 
-namespace osrm
-{
-namespace guidance
+namespace osrm::guidance
 {
 namespace detail
 {
@@ -116,7 +114,6 @@ template <storage::Ownership Ownership> class TurnDataContainerImpl
 using TurnDataExternalContainer = detail::TurnDataContainerImpl<storage::Ownership::External>;
 using TurnDataContainer = detail::TurnDataContainerImpl<storage::Ownership::Container>;
 using TurnDataView = detail::TurnDataContainerImpl<storage::Ownership::View>;
-} // namespace guidance
 } // namespace osrm
 
 #endif
diff --git a/include/guidance/turn_discovery.hpp b/include/guidance/turn_discovery.hpp
index 52b72f846..b53bc8387 100644
--- a/include/guidance/turn_discovery.hpp
+++ b/include/guidance/turn_discovery.hpp
@@ -20,10 +20,7 @@ namespace extractor
 class CompressedEdgeContainer;
 }
 
-namespace guidance
-{
-
-namespace lanes
+namespace guidance::lanes
 {
 
 // OSRM processes edges by looking at a via_edge, coming into an intersection. For turn lanes, we
@@ -45,7 +42,6 @@ bool findPreviousIntersection(
     EdgeID &result_via_edge,
     extractor::intersection::IntersectionView &result_intersection);
 
-} // namespace lanes
 } // namespace guidance
 } // namespace osrm
 
diff --git a/include/guidance/turn_handler.hpp b/include/guidance/turn_handler.hpp
index 63470f690..73bcb7369 100644
--- a/include/guidance/turn_handler.hpp
+++ b/include/guidance/turn_handler.hpp
@@ -17,9 +17,7 @@
 #include <utility>
 #include <vector>
 
-namespace osrm
-{
-namespace guidance
+namespace osrm::guidance
 {
 
 // Intersection handlers deal with all issues related to intersections.
@@ -111,7 +109,6 @@ class TurnHandler final : public IntersectionHandler
                                   const std::size_t up_to) const;
 };
 
-} // namespace guidance
 } // namespace osrm
 
 #endif /*OSRM_GUIDANCE_TURN_HANDLER_HPP_*/
diff --git a/include/guidance/turn_instruction.hpp b/include/guidance/turn_instruction.hpp
index ffd4e952d..a57836584 100644
--- a/include/guidance/turn_instruction.hpp
+++ b/include/guidance/turn_instruction.hpp
@@ -8,9 +8,7 @@
 #include "util/attributes.hpp"
 #include "util/typedefs.hpp"
 
-namespace osrm
-{
-namespace guidance
+namespace osrm::guidance
 {
 
 // direction modifiers based on angle
@@ -393,7 +391,6 @@ inline std::string instructionModifierToString(const DirectionModifier::Enum mod
     return detail::modifier_names[static_cast<std::size_t>(modifier)];
 }
 
-} // namespace guidance
 } // namespace osrm
 
 #endif // OSRM_GUIDANCE_TURN_INSTRUCTION_HPP_
diff --git a/include/guidance/turn_lane_augmentation.hpp b/include/guidance/turn_lane_augmentation.hpp
index e6f5cd26b..efb14a345 100644
--- a/include/guidance/turn_lane_augmentation.hpp
+++ b/include/guidance/turn_lane_augmentation.hpp
@@ -5,19 +5,13 @@
 #include "guidance/turn_lane_data.hpp"
 #include "util/attributes.hpp"
 
-namespace osrm
-{
-namespace guidance
-{
-namespace lanes
+namespace osrm::guidance::lanes
 {
 
 OSRM_ATTR_WARN_UNUSED
 LaneDataVector handleNoneValueAtSimpleTurn(LaneDataVector lane_data,
                                            const Intersection &intersection);
 
-} // namespace lanes
-} // namespace guidance
 } // namespace osrm
 
 #endif /* OSRM_GUIDANCE_TURN_LANE_AUGMENTATION_HPP_ */
diff --git a/include/guidance/turn_lane_data.hpp b/include/guidance/turn_lane_data.hpp
index 8e7bc7351..302ca4496 100644
--- a/include/guidance/turn_lane_data.hpp
+++ b/include/guidance/turn_lane_data.hpp
@@ -6,11 +6,7 @@
 #include "util/typedefs.hpp"
 #include <vector>
 
-namespace osrm
-{
-namespace guidance
-{
-namespace lanes
+namespace osrm::guidance::lanes
 {
 
 struct TurnLaneData
@@ -37,9 +33,6 @@ LaneDataVector::iterator findTag(const extractor::TurnLaneType::Mask tag, LaneDa
 
 // Returns true if any of the queried tags is contained
 bool hasTag(const extractor::TurnLaneType::Mask tag, const LaneDataVector &data);
-} // namespace lanes
-
-} // namespace guidance
 } // namespace osrm
 
 #endif /* OSRM_GUIDANCE_TURN_LANE_DATA_HPP_ */
diff --git a/include/guidance/turn_lane_handler.hpp b/include/guidance/turn_lane_handler.hpp
index 180bc84b3..cfbb8c54d 100644
--- a/include/guidance/turn_lane_handler.hpp
+++ b/include/guidance/turn_lane_handler.hpp
@@ -22,14 +22,7 @@
 #include <utility>
 #include <vector>
 
-namespace osrm
-{
-namespace guidance
-{
-
-// Given an Intersection, the graph to access the data and the turn lanes, the turn lane matcher
-// assigns appropriate turn tupels to the different turns.
-namespace lanes
+namespace osrm::guidance::lanes
 {
 
 namespace
@@ -140,8 +133,6 @@ class TurnLaneHandler
                          LaneDataVector &lane_data) const;
 };
 
-} // namespace lanes
-} // namespace guidance
 } // namespace osrm
 
 #endif // OSRM_EXTRACTOR_GUIDANCE_TURN_LANE_HANDLER_HPP_
diff --git a/include/guidance/turn_lane_matcher.hpp b/include/guidance/turn_lane_matcher.hpp
index 8d2ed0597..241968fca 100644
--- a/include/guidance/turn_lane_matcher.hpp
+++ b/include/guidance/turn_lane_matcher.hpp
@@ -9,11 +9,7 @@
 #include "util/guidance/turn_lanes.hpp"
 #include "util/node_based_graph.hpp"
 
-namespace osrm
-{
-namespace guidance
-{
-namespace lanes
+namespace osrm::guidance::lanes
 {
 
 // Translate Turn Lane Tags into a matching modifier
@@ -45,8 +41,6 @@ Intersection triviallyMatchLanesToTurns(Intersection intersection,
                                         const LaneDescriptionID lane_string_id,
                                         util::guidance::LaneDataIdMap &lane_data_to_id);
 
-} // namespace lanes
-} // namespace guidance
 } // namespace osrm
 
 #endif /*OSRM_GUIDANCE_TURN_LANE_MATCHER_HPP_*/
diff --git a/include/osrm/osrm_fwd.hpp b/include/osrm/osrm_fwd.hpp
index e1b0ee772..5e32348da 100644
--- a/include/osrm/osrm_fwd.hpp
+++ b/include/osrm/osrm_fwd.hpp
@@ -34,12 +34,9 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 namespace osrm
 {
 
-namespace util
-{
-namespace json
+namespace util::json
 {
 struct Object;
-} // namespace json
 } // namespace util
 
 namespace engine
diff --git a/include/partitioner/bisection_graph.hpp b/include/partitioner/bisection_graph.hpp
index e8dc80817..8c697af64 100644
--- a/include/partitioner/bisection_graph.hpp
+++ b/include/partitioner/bisection_graph.hpp
@@ -14,9 +14,7 @@
 #include <iterator>
 #include <utility>
 
-namespace osrm
-{
-namespace partitioner
+namespace osrm::partitioner
 {
 
 // Node in the bisection graph. We require the original node id (since we remap the nodes all the
@@ -111,7 +109,6 @@ std::vector<BisectionInputEdge> adaptToBisectionEdge(std::vector<InputEdge> edge
     return result;
 }
 
-} // namespace partitioner
 } // namespace osrm
 
 #endif // OSRM_PARTITIONER_BISECTION_GRAPH_HPP_
diff --git a/include/partitioner/bisection_graph_view.hpp b/include/partitioner/bisection_graph_view.hpp
index 04336a08f..c050607f1 100644
--- a/include/partitioner/bisection_graph_view.hpp
+++ b/include/partitioner/bisection_graph_view.hpp
@@ -10,9 +10,7 @@
 #include <cstddef>
 #include <cstdint>
 
-namespace osrm
-{
-namespace partitioner
+namespace osrm::partitioner
 {
 
 // Non-owning immutable sub-graph view into a base graph.
@@ -64,7 +62,6 @@ class BisectionGraphView
     const BisectionGraph::ConstNodeIterator end;
 };
 
-} // namespace partitioner
 } // namespace osrm
 
 #endif // OSRM_PARTITIONER_GRAPHVIEW_HPP_
diff --git a/include/partitioner/bisection_to_partition.hpp b/include/partitioner/bisection_to_partition.hpp
index 03a37f19b..8c26c810d 100644
--- a/include/partitioner/bisection_to_partition.hpp
+++ b/include/partitioner/bisection_to_partition.hpp
@@ -6,9 +6,7 @@
 
 #include <vector>
 
-namespace osrm
-{
-namespace partitioner
+namespace osrm::partitioner
 {
 
 using Partition = std::vector<CellID>;
@@ -17,7 +15,6 @@ using Partition = std::vector<CellID>;
 std::tuple<std::vector<Partition>, std::vector<std::uint32_t>>
 bisectionToPartition(const std::vector<BisectionID> &node_to_bisection_id,
                      const std::vector<std::size_t> &max_cell_sizes);
-} // namespace partitioner
 } // namespace osrm
 
 #endif
diff --git a/include/partitioner/cell_statistics.hpp b/include/partitioner/cell_statistics.hpp
index 17b750e79..46dac654d 100644
--- a/include/partitioner/cell_statistics.hpp
+++ b/include/partitioner/cell_statistics.hpp
@@ -6,9 +6,7 @@
 
 #include <unordered_set>
 
-namespace osrm
-{
-namespace partitioner
+namespace osrm::partitioner
 {
 template <typename Partition, typename CellStorage>
 void printCellStatistics(const Partition &partition, const CellStorage &storage)
@@ -48,7 +46,6 @@ void printCellStatistics(const Partition &partition, const CellStorage &storage)
                     << (2 * entries * sizeof(EdgeWeight)) << " bytes)";
     }
 }
-} // namespace partitioner
 } // namespace osrm
 
 #endif
diff --git a/include/partitioner/cell_storage.hpp b/include/partitioner/cell_storage.hpp
index db41405c2..751826c66 100644
--- a/include/partitioner/cell_storage.hpp
+++ b/include/partitioner/cell_storage.hpp
@@ -24,9 +24,7 @@
 #include <utility>
 #include <vector>
 
-namespace osrm
-{
-namespace partitioner
+namespace osrm::partitioner
 {
 namespace detail
 {
@@ -448,7 +446,6 @@ template <storage::Ownership Ownership> class CellStorageImpl
     Vector<std::uint64_t> level_to_cell_offset;
 };
 } // namespace detail
-} // namespace partitioner
 } // namespace osrm
 
 #endif // OSRM_PARTITIONER_CUSTOMIZE_CELL_STORAGE_HPP
diff --git a/include/partitioner/dinic_max_flow.hpp b/include/partitioner/dinic_max_flow.hpp
index 5efffe93c..565f39d6c 100644
--- a/include/partitioner/dinic_max_flow.hpp
+++ b/include/partitioner/dinic_max_flow.hpp
@@ -10,9 +10,7 @@
 #include <utility>
 #include <vector>
 
-namespace osrm
-{
-namespace partitioner
+namespace osrm::partitioner
 {
 
 class DinicMaxFlow
@@ -88,7 +86,6 @@ class DinicMaxFlow
                    const std::size_t flow_value) const;
 };
 
-} // namespace partitioner
 } // namespace osrm
 
 // Implementation of Dinics [1] algorithm for max-flow/min-cut.
diff --git a/include/partitioner/edge_based_graph.hpp b/include/partitioner/edge_based_graph.hpp
index a0f6e1986..51422d981 100644
--- a/include/partitioner/edge_based_graph.hpp
+++ b/include/partitioner/edge_based_graph.hpp
@@ -14,9 +14,7 @@
 #include <memory>
 #include <vector>
 
-namespace osrm
-{
-namespace partitioner
+namespace osrm::partitioner
 {
 
 struct EdgeBasedGraphEdgeData : extractor::EdgeBasedEdge::EdgeData
@@ -53,7 +51,6 @@ struct DynamicEdgeBasedGraphEdge : DynamicEdgeBasedGraph::InputEdge
     using Base = DynamicEdgeBasedGraph::InputEdge;
     using Base::Base;
 };
-} // namespace partitioner
 } // namespace osrm
 
 #endif
diff --git a/include/partitioner/edge_based_graph_reader.hpp b/include/partitioner/edge_based_graph_reader.hpp
index b2dd7a55c..817b65e82 100644
--- a/include/partitioner/edge_based_graph_reader.hpp
+++ b/include/partitioner/edge_based_graph_reader.hpp
@@ -21,9 +21,7 @@
 #include <memory>
 #include <vector>
 
-namespace osrm
-{
-namespace partitioner
+namespace osrm::partitioner
 {
 
 // Bidirectional (s,t) to (s,t) and (t,s)
@@ -198,7 +196,6 @@ inline DynamicEdgeBasedGraph LoadEdgeBasedGraph(const boost::filesystem::path &p
     return DynamicEdgeBasedGraph(number_of_edge_based_nodes, tidied, checksum);
 }
 
-} // namespace partitioner
 } // namespace osrm
 
 #endif
diff --git a/include/partitioner/files.hpp b/include/partitioner/files.hpp
index fe96d5c50..0b389ec18 100644
--- a/include/partitioner/files.hpp
+++ b/include/partitioner/files.hpp
@@ -5,11 +5,7 @@
 
 #include "storage/io.hpp"
 
-namespace osrm
-{
-namespace partitioner
-{
-namespace files
+namespace osrm::partitioner::files
 {
 
 // read .osrm.partition file
@@ -96,8 +92,6 @@ inline void writeGraph(const boost::filesystem::path &path,
     writer.WriteFrom("/mld/connectivity_checksum", connectivity_checksum);
     serialization::write(writer, "/mld/multilevelgraph", graph);
 }
-} // namespace files
-} // namespace partitioner
 } // namespace osrm
 
 #endif
diff --git a/include/partitioner/inertial_flow.hpp b/include/partitioner/inertial_flow.hpp
index 25e57d6a6..18a1553d9 100644
--- a/include/partitioner/inertial_flow.hpp
+++ b/include/partitioner/inertial_flow.hpp
@@ -4,9 +4,7 @@
 #include "partitioner/bisection_graph_view.hpp"
 #include "partitioner/dinic_max_flow.hpp"
 
-namespace osrm
-{
-namespace partitioner
+namespace osrm::partitioner
 {
 
 DinicMaxFlow::MinCut computeInertialFlowCut(const BisectionGraphView &view,
@@ -14,7 +12,6 @@ DinicMaxFlow::MinCut computeInertialFlowCut(const BisectionGraphView &view,
                                             const double balance,
                                             const double source_sink_rate);
 
-} // namespace partitioner
 } // namespace osrm
 
 #endif // OSRM_PARTITIONER_INERTIAL_FLOW_HPP_
diff --git a/include/partitioner/multi_level_graph.hpp b/include/partitioner/multi_level_graph.hpp
index d4a9bcf4e..0febf305e 100644
--- a/include/partitioner/multi_level_graph.hpp
+++ b/include/partitioner/multi_level_graph.hpp
@@ -15,10 +15,7 @@
 #include <boost/iterator/permutation_iterator.hpp>
 #include <boost/range/combine.hpp>
 
-namespace osrm
-{
-
-namespace partitioner
+namespace osrm::partitioner
 {
 template <typename EdgeDataT, storage::Ownership Ownership> class MultiLevelGraph;
 
@@ -236,7 +233,6 @@ class MultiLevelGraph : public util::StaticGraph<EdgeDataT, Ownership>
 
 using MultiLevelEdgeBasedGraph =
     MultiLevelGraph<EdgeBasedGraphEdgeData, storage::Ownership::Container>;
-} // namespace partitioner
 } // namespace osrm
 
 #endif
diff --git a/include/partitioner/multi_level_partition.hpp b/include/partitioner/multi_level_partition.hpp
index bbe0978d6..fc0f4077b 100644
--- a/include/partitioner/multi_level_partition.hpp
+++ b/include/partitioner/multi_level_partition.hpp
@@ -20,9 +20,7 @@
 
 #include <boost/range/adaptor/reversed.hpp>
 
-namespace osrm
-{
-namespace partitioner
+namespace osrm::partitioner
 {
 namespace detail
 {
@@ -344,7 +342,6 @@ inline MultiLevelPartitionImpl<storage::Ownership::View>::MultiLevelPartitionImp
 {
 }
 } // namespace detail
-} // namespace partitioner
 } // namespace osrm
 
 #endif
diff --git a/include/partitioner/partition_graph.hpp b/include/partitioner/partition_graph.hpp
index 21c3556c1..b0dbde9da 100644
--- a/include/partitioner/partition_graph.hpp
+++ b/include/partitioner/partition_graph.hpp
@@ -10,9 +10,7 @@
 #include "util/typedefs.hpp"
 #include <boost/range/iterator_range.hpp>
 
-namespace osrm
-{
-namespace partitioner
+namespace osrm::partitioner
 {
 
 // forward declaration to allow finding friends
@@ -156,7 +154,6 @@ template <typename NodeEntryT, typename EdgeEntryT> class RemappableGraph
     std::vector<EdgeT> edges;
 };
 
-} // namespace partitioner
 } // namespace osrm
 
 #endif // OSRM_PARTITIONER_GRAPH_HPP_
diff --git a/include/partitioner/partitioner.hpp b/include/partitioner/partitioner.hpp
index 30c518524..e254809ac 100644
--- a/include/partitioner/partitioner.hpp
+++ b/include/partitioner/partitioner.hpp
@@ -3,9 +3,7 @@
 
 #include "partitioner/partitioner_config.hpp"
 
-namespace osrm
-{
-namespace partitioner
+namespace osrm::partitioner
 {
 
 // tool access to the recursive partitioner
@@ -15,7 +13,6 @@ class Partitioner
     int Run(const PartitionerConfig &config);
 };
 
-} // namespace partitioner
 } // namespace osrm
 
 #endif // OSRM_PARTITIONER_PARTITIONER_HPP_
diff --git a/include/partitioner/partitioner_config.hpp b/include/partitioner/partitioner_config.hpp
index 6eb3581da..7522cb4e0 100644
--- a/include/partitioner/partitioner_config.hpp
+++ b/include/partitioner/partitioner_config.hpp
@@ -8,9 +8,7 @@
 
 #include "storage/io_config.hpp"
 
-namespace osrm
-{
-namespace partitioner
+namespace osrm::partitioner
 {
 
 struct PartitionerConfig final : storage::IOConfig
@@ -44,7 +42,6 @@ struct PartitionerConfig final : storage::IOConfig
     std::size_t small_component_size;
     std::vector<std::size_t> max_cell_sizes;
 };
-} // namespace partitioner
 } // namespace osrm
 
 #endif // OSRM_PARTITIONER_CONFIG_HPP
diff --git a/include/partitioner/recursive_bisection.hpp b/include/partitioner/recursive_bisection.hpp
index ddbd2bb65..4985527dc 100644
--- a/include/partitioner/recursive_bisection.hpp
+++ b/include/partitioner/recursive_bisection.hpp
@@ -8,9 +8,7 @@
 #include <cstddef>
 #include <vector>
 
-namespace osrm
-{
-namespace partitioner
+namespace osrm::partitioner
 {
 
 class RecursiveBisection
@@ -32,7 +30,6 @@ class RecursiveBisection
     RecursiveBisectionState internal_state;
 };
 
-} // namespace partitioner
 } // namespace osrm
 
 #endif // OSRM_PARTITIONER_RECURSIVE_BISECTION_HPP_
diff --git a/include/partitioner/recursive_bisection_state.hpp b/include/partitioner/recursive_bisection_state.hpp
index 8621fd765..933219fcc 100644
--- a/include/partitioner/recursive_bisection_state.hpp
+++ b/include/partitioner/recursive_bisection_state.hpp
@@ -9,9 +9,7 @@
 #include "partitioner/bisection_graph_view.hpp"
 #include "util/typedefs.hpp"
 
-namespace osrm
-{
-namespace partitioner
+namespace osrm::partitioner
 {
 
 // Keeps track of the bisection ids, modifies the graph accordingly, splitting it into a left/right
@@ -50,7 +48,6 @@ class RecursiveBisectionState
     std::vector<BisectionID> bisection_ids;
 };
 
-} // namespace partitioner
 } // namespace osrm
 
 #endif // OSRM_PARTITIONER_RECURSIVE_BISECTION_STATE_HPP_
diff --git a/include/partitioner/remove_unconnected.hpp b/include/partitioner/remove_unconnected.hpp
index 2e379fa71..cb25a77db 100644
--- a/include/partitioner/remove_unconnected.hpp
+++ b/include/partitioner/remove_unconnected.hpp
@@ -9,9 +9,7 @@
 #include <algorithm>
 #include <vector>
 
-namespace osrm
-{
-namespace partitioner
+namespace osrm::partitioner
 {
 using Partition = std::vector<CellID>;
 
@@ -109,7 +107,6 @@ std::size_t removeUnconnectedBoundaryNodes(const GraphT &edge_based_graph,
 
     return num_unconnected;
 }
-} // namespace partitioner
 } // namespace osrm
 
 #endif
diff --git a/include/partitioner/renumber.hpp b/include/partitioner/renumber.hpp
index b29c65c6b..c1d8f5851 100644
--- a/include/partitioner/renumber.hpp
+++ b/include/partitioner/renumber.hpp
@@ -12,9 +12,7 @@
 #include "util/dynamic_graph.hpp"
 #include "util/static_graph.hpp"
 
-namespace osrm
-{
-namespace partitioner
+namespace osrm::partitioner
 {
 std::vector<std::uint32_t> makePermutation(const DynamicEdgeBasedGraph &graph,
                                            const std::vector<Partition> &partitions);
@@ -93,7 +91,6 @@ inline void renumber(std::vector<extractor::StorageManeuverOverride> &maneuver_o
     }
 }
 
-} // namespace partitioner
 } // namespace osrm
 
 #endif
diff --git a/include/partitioner/reorder_first_last.hpp b/include/partitioner/reorder_first_last.hpp
index da2d04157..728f41958 100644
--- a/include/partitioner/reorder_first_last.hpp
+++ b/include/partitioner/reorder_first_last.hpp
@@ -7,9 +7,7 @@
 #include <cstddef>
 #include <iterator>
 
-namespace osrm
-{
-namespace partitioner
+namespace osrm::partitioner
 {
 
 // Reorders the first n elements in the range to satisfy the comparator,
@@ -49,7 +47,6 @@ void reorderFirstLast(RandomAccessRange &rng, std::size_t n, Compare comp)
     return reorderFirstLast(begin(rng), end(rng), n, comp);
 }
 
-} // namespace partitioner
 } // namespace osrm
 
 #endif
diff --git a/include/partitioner/serialization.hpp b/include/partitioner/serialization.hpp
index 55e105102..ee1b0ebef 100644
--- a/include/partitioner/serialization.hpp
+++ b/include/partitioner/serialization.hpp
@@ -12,11 +12,7 @@
 #include "storage/shared_memory_ownership.hpp"
 #include "storage/tar.hpp"
 
-namespace osrm
-{
-namespace partitioner
-{
-namespace serialization
+namespace osrm::partitioner::serialization
 {
 
 template <storage::Ownership Ownership>
@@ -65,8 +61,6 @@ inline void write(storage::tar::FileWriter &writer,
     storage::serialization::write(
         writer, name + "/level_to_cell_offset", storage.level_to_cell_offset);
 }
-} // namespace serialization
-} // namespace partitioner
 } // namespace osrm
 
 #endif
diff --git a/include/partitioner/tarjan_graph_wrapper.hpp b/include/partitioner/tarjan_graph_wrapper.hpp
index 515ca2041..7027a1238 100644
--- a/include/partitioner/tarjan_graph_wrapper.hpp
+++ b/include/partitioner/tarjan_graph_wrapper.hpp
@@ -5,9 +5,7 @@
 #include "util/integer_range.hpp"
 #include "util/typedefs.hpp"
 
-namespace osrm
-{
-namespace partitioner
+namespace osrm::partitioner
 {
 
 class TarjanGraphWrapper
@@ -23,7 +21,6 @@ class TarjanGraphWrapper
     const BisectionGraph &bisection_graph;
 };
 
-} // namespace partitioner
 } // namespace osrm
 
 #endif // OSRM_PARTITIONER_TARJAN_GRAPH_WRAPPER_HPP_
diff --git a/include/server/api/base_parameters_grammar.hpp b/include/server/api/base_parameters_grammar.hpp
index 827855acf..4c43016f5 100644
--- a/include/server/api/base_parameters_grammar.hpp
+++ b/include/server/api/base_parameters_grammar.hpp
@@ -14,11 +14,7 @@
 #include <limits>
 #include <string>
 
-namespace osrm
-{
-namespace server
-{
-namespace api
+namespace osrm::server::api
 {
 
 namespace
@@ -235,8 +231,6 @@ struct BaseParametersGrammar : boost::spirit::qi::grammar<Iterator, Signature>
     qi::symbols<char, engine::Approach> approach_type;
     qi::symbols<char, engine::api::BaseParameters::SnappingType> snapping_type;
 };
-} // namespace api
-} // namespace server
 } // namespace osrm
 
 #endif
diff --git a/include/server/api/match_parameter_grammar.hpp b/include/server/api/match_parameter_grammar.hpp
index 9893b01db..855482856 100644
--- a/include/server/api/match_parameter_grammar.hpp
+++ b/include/server/api/match_parameter_grammar.hpp
@@ -7,11 +7,7 @@
 #include <boost/spirit/include/phoenix.hpp>
 #include <boost/spirit/include/qi.hpp>
 
-namespace osrm
-{
-namespace server
-{
-namespace api
+namespace osrm::server::api
 {
 
 namespace
@@ -62,8 +58,6 @@ struct MatchParametersGrammar final : public RouteParametersGrammar<Iterator, Si
 
     qi::symbols<char, engine::api::MatchParameters::GapsType> gaps_type;
 };
-} // namespace api
-} // namespace server
 } // namespace osrm
 
 #endif
diff --git a/include/server/api/nearest_parameter_grammar.hpp b/include/server/api/nearest_parameter_grammar.hpp
index 8327a9503..b7b8bb502 100644
--- a/include/server/api/nearest_parameter_grammar.hpp
+++ b/include/server/api/nearest_parameter_grammar.hpp
@@ -7,11 +7,7 @@
 #include <boost/spirit/include/phoenix.hpp>
 #include <boost/spirit/include/qi.hpp>
 
-namespace osrm
-{
-namespace server
-{
-namespace api
+namespace osrm::server::api
 {
 
 namespace
@@ -40,8 +36,6 @@ struct NearestParametersGrammar final : public BaseParametersGrammar<Iterator, S
     qi::rule<Iterator, Signature> root_rule;
     qi::rule<Iterator, Signature> nearest_rule;
 };
-} // namespace api
-} // namespace server
 } // namespace osrm
 
 #endif
diff --git a/include/server/api/parameters_parser.hpp b/include/server/api/parameters_parser.hpp
index 05e257b53..9492226bf 100644
--- a/include/server/api/parameters_parser.hpp
+++ b/include/server/api/parameters_parser.hpp
@@ -8,11 +8,7 @@
 
 #include <type_traits>
 
-namespace osrm
-{
-namespace server
-{
-namespace api
+namespace osrm::server::api
 {
 
 // Note: this file provides only the interface for the generic parseParameters function.
@@ -43,8 +39,6 @@ boost::optional<ParameterT> parseParameters(std::string options_string)
     return parseParameters<ParameterT>(first, last);
 }
 
-} // namespace api
-} // namespace server
 } // namespace osrm
 
 #endif
diff --git a/include/server/api/parsed_url.hpp b/include/server/api/parsed_url.hpp
index b4abf49c5..2e444c48b 100644
--- a/include/server/api/parsed_url.hpp
+++ b/include/server/api/parsed_url.hpp
@@ -6,11 +6,7 @@
 #include <string>
 #include <vector>
 
-namespace osrm
-{
-namespace server
-{
-namespace api
+namespace osrm::server::api
 {
 
 struct ParsedURL final
@@ -22,8 +18,6 @@ struct ParsedURL final
     std::size_t prefix_length;
 };
 
-} // namespace api
-} // namespace server
 } // namespace osrm
 
 #endif
diff --git a/include/server/api/route_parameters_grammar.hpp b/include/server/api/route_parameters_grammar.hpp
index df5fb52df..544c179c6 100644
--- a/include/server/api/route_parameters_grammar.hpp
+++ b/include/server/api/route_parameters_grammar.hpp
@@ -7,11 +7,7 @@
 #include <boost/spirit/include/phoenix.hpp>
 #include <boost/spirit/include/qi.hpp>
 
-namespace osrm
-{
-namespace server
-{
-namespace api
+namespace osrm::server::api
 {
 
 namespace
@@ -113,8 +109,6 @@ struct RouteParametersGrammar : public BaseParametersGrammar<Iterator, Signature
     qi::symbols<char, engine::api::RouteParameters::OverviewType> overview_type;
     qi::symbols<char, engine::api::RouteParameters::AnnotationsType> annotations_type;
 };
-} // namespace api
-} // namespace server
 } // namespace osrm
 
 #endif
diff --git a/include/server/api/table_parameter_grammar.hpp b/include/server/api/table_parameter_grammar.hpp
index c88f85299..d810f85c1 100644
--- a/include/server/api/table_parameter_grammar.hpp
+++ b/include/server/api/table_parameter_grammar.hpp
@@ -7,11 +7,7 @@
 #include <boost/spirit/include/phoenix.hpp>
 #include <boost/spirit/include/qi.hpp>
 
-namespace osrm
-{
-namespace server
-{
-namespace api
+namespace osrm::server::api
 {
 
 namespace
@@ -106,8 +102,6 @@ struct TableParametersGrammar : public BaseParametersGrammar<Iterator, Signature
         fallback_coordinate_type;
     qi::real_parser<double, json_policy> double_;
 };
-} // namespace api
-} // namespace server
 } // namespace osrm
 
 #endif
diff --git a/include/server/api/tile_parameter_grammar.hpp b/include/server/api/tile_parameter_grammar.hpp
index 8c22b3837..dfd7351a2 100644
--- a/include/server/api/tile_parameter_grammar.hpp
+++ b/include/server/api/tile_parameter_grammar.hpp
@@ -11,11 +11,7 @@
 
 #include <string>
 
-namespace osrm
-{
-namespace server
-{
-namespace api
+namespace osrm::server::api
 {
 
 namespace
@@ -40,8 +36,6 @@ struct TileParametersGrammar final : boost::spirit::qi::grammar<Iterator, Signat
   private:
     qi::rule<Iterator, Signature> root_rule;
 };
-} // namespace api
-} // namespace server
 } // namespace osrm
 
 #endif
diff --git a/include/server/api/trip_parameter_grammar.hpp b/include/server/api/trip_parameter_grammar.hpp
index ecb14db50..c3318ddac 100644
--- a/include/server/api/trip_parameter_grammar.hpp
+++ b/include/server/api/trip_parameter_grammar.hpp
@@ -7,11 +7,7 @@
 #include <boost/spirit/include/phoenix.hpp>
 #include <boost/spirit/include/qi.hpp>
 
-namespace osrm
-{
-namespace server
-{
-namespace api
+namespace osrm::server::api
 {
 
 namespace
@@ -60,8 +56,6 @@ struct TripParametersGrammar final : public RouteParametersGrammar<Iterator, Sig
     qi::symbols<char, engine::api::TripParameters::SourceType> source_type;
     qi::symbols<char, engine::api::TripParameters::DestinationType> destination_type;
 };
-} // namespace api
-} // namespace server
 } // namespace osrm
 
 #endif
diff --git a/include/server/api/url_parser.hpp b/include/server/api/url_parser.hpp
index 35a3e0a60..f166ea38c 100644
--- a/include/server/api/url_parser.hpp
+++ b/include/server/api/url_parser.hpp
@@ -7,11 +7,7 @@
 
 #include <string>
 
-namespace osrm
-{
-namespace server
-{
-namespace api
+namespace osrm::server::api
 {
 
 // Starts parsing and iter and modifies it until iter == end or parsing failed
@@ -22,8 +18,6 @@ inline boost::optional<ParsedURL> parseURL(std::string url_string)
     auto iter = url_string.begin();
     return parseURL(iter, url_string.end());
 }
-} // namespace api
-} // namespace server
 } // namespace osrm
 
 #endif
diff --git a/include/server/connection.hpp b/include/server/connection.hpp
index df5b47d26..5bc84a824 100644
--- a/include/server/connection.hpp
+++ b/include/server/connection.hpp
@@ -26,9 +26,7 @@ template <class T> T *get_pointer(std::shared_ptr<T> &p) { return p.get(); }
 
 #endif
 
-namespace osrm
-{
-namespace server
+namespace osrm::server
 {
 
 class RequestHandler;
@@ -76,7 +74,6 @@ class Connection : public std::enable_shared_from_this<Connection>
     short processed_requests = 512;
     short keepalive_timeout = 5; // In seconds
 };
-} // namespace server
 } // namespace osrm
 
 #endif // CONNECTION_HPP
diff --git a/include/server/http/compression_type.hpp b/include/server/http/compression_type.hpp
index 620ca5859..1e3d18fee 100644
--- a/include/server/http/compression_type.hpp
+++ b/include/server/http/compression_type.hpp
@@ -1,11 +1,7 @@
 #ifndef COMPRESSION_TYPE_HPP
 #define COMPRESSION_TYPE_HPP
 
-namespace osrm
-{
-namespace server
-{
-namespace http
+namespace osrm::server::http
 {
 
 enum compression_type
@@ -14,8 +10,6 @@ enum compression_type
     gzip_rfc1952,
     deflate_rfc1951
 };
-}
-} // namespace server
 } // namespace osrm
 
 #endif // COMPRESSION_TYPE_HPP
diff --git a/include/server/http/header.hpp b/include/server/http/header.hpp
index 8ceb5ae9e..1b1bc4f08 100644
--- a/include/server/http/header.hpp
+++ b/include/server/http/header.hpp
@@ -4,11 +4,7 @@
 #include <algorithm>
 #include <string>
 
-namespace osrm
-{
-namespace server
-{
-namespace http
+namespace osrm::server::http
 {
 
 struct header
@@ -27,8 +23,6 @@ struct header
     std::string name;
     std::string value;
 };
-} // namespace http
-} // namespace server
 } // namespace osrm
 
 #endif // HEADER_HPP
diff --git a/include/server/http/reply.hpp b/include/server/http/reply.hpp
index a7b444691..55dd8f1b6 100644
--- a/include/server/http/reply.hpp
+++ b/include/server/http/reply.hpp
@@ -7,11 +7,7 @@
 
 #include <vector>
 
-namespace osrm
-{
-namespace server
-{
-namespace http
+namespace osrm::server::http
 {
 
 class reply
@@ -38,8 +34,6 @@ class reply
     std::string status_to_string(reply::status_type status);
     boost::asio::const_buffer status_to_buffer(reply::status_type status);
 };
-} // namespace http
-} // namespace server
 } // namespace osrm
 
 #endif // REPLY_HPP
diff --git a/include/server/http/request.hpp b/include/server/http/request.hpp
index 69830ec0d..34acaf9fc 100644
--- a/include/server/http/request.hpp
+++ b/include/server/http/request.hpp
@@ -5,11 +5,7 @@
 
 #include <string>
 
-namespace osrm
-{
-namespace server
-{
-namespace http
+namespace osrm::server::http
 {
 
 struct request
@@ -20,8 +16,6 @@ struct request
     std::string connection;
     boost::asio::ip::address endpoint;
 };
-} // namespace http
-} // namespace server
 } // namespace osrm
 
 #endif // REQUEST_HPP
diff --git a/include/server/request_handler.hpp b/include/server/request_handler.hpp
index e1c47fced..62864dab7 100644
--- a/include/server/request_handler.hpp
+++ b/include/server/request_handler.hpp
@@ -5,9 +5,7 @@
 
 #include <string>
 
-namespace osrm
-{
-namespace server
+namespace osrm::server
 {
 
 namespace http
@@ -31,7 +29,6 @@ class RequestHandler
   private:
     std::unique_ptr<ServiceHandlerInterface> service_handler;
 };
-} // namespace server
 } // namespace osrm
 
 #endif // REQUEST_HANDLER_HPP
diff --git a/include/server/request_parser.hpp b/include/server/request_parser.hpp
index 5af1911c9..7b27ccf2d 100644
--- a/include/server/request_parser.hpp
+++ b/include/server/request_parser.hpp
@@ -6,9 +6,7 @@
 
 #include <tuple>
 
-namespace osrm
-{
-namespace server
+namespace osrm::server
 {
 
 namespace http
@@ -69,7 +67,6 @@ class RequestParser
     http::header current_header;
     http::compression_type selected_compression;
 };
-} // namespace server
 } // namespace osrm
 
 #endif // REQUEST_PARSER_HPP
diff --git a/include/server/server.hpp b/include/server/server.hpp
index 0b87e50ae..eb50d02f6 100644
--- a/include/server/server.hpp
+++ b/include/server/server.hpp
@@ -24,9 +24,7 @@
 #include <thread>
 #include <vector>
 
-namespace osrm
-{
-namespace server
+namespace osrm::server
 {
 
 class Server
@@ -113,7 +111,6 @@ class Server
     boost::asio::ip::tcp::acceptor acceptor;
     std::shared_ptr<Connection> new_connection;
 };
-} // namespace server
 } // namespace osrm
 
 #endif // SERVER_HPP
diff --git a/include/server/service/base_service.hpp b/include/server/service/base_service.hpp
index d8e88e72e..1324ef60d 100644
--- a/include/server/service/base_service.hpp
+++ b/include/server/service/base_service.hpp
@@ -10,11 +10,7 @@
 #include <string>
 #include <vector>
 
-namespace osrm
-{
-namespace server
-{
-namespace service
+namespace osrm::server::service
 {
 
 class BaseService
@@ -31,8 +27,6 @@ class BaseService
   protected:
     OSRM &routing_machine;
 };
-} // namespace service
-} // namespace server
 } // namespace osrm
 
 #endif
diff --git a/include/server/service/match_service.hpp b/include/server/service/match_service.hpp
index df9b81ace..09ab65389 100644
--- a/include/server/service/match_service.hpp
+++ b/include/server/service/match_service.hpp
@@ -10,11 +10,7 @@
 #include <string>
 #include <vector>
 
-namespace osrm
-{
-namespace server
-{
-namespace service
+namespace osrm::server::service
 {
 
 class MatchService final : public BaseService
@@ -28,8 +24,6 @@ class MatchService final : public BaseService
 
     unsigned GetVersion() final override { return 1; }
 };
-} // namespace service
-} // namespace server
 } // namespace osrm
 
 #endif
diff --git a/include/server/service/nearest_service.hpp b/include/server/service/nearest_service.hpp
index 06495ea59..40d0b56b9 100644
--- a/include/server/service/nearest_service.hpp
+++ b/include/server/service/nearest_service.hpp
@@ -10,11 +10,7 @@
 #include <string>
 #include <vector>
 
-namespace osrm
-{
-namespace server
-{
-namespace service
+namespace osrm::server::service
 {
 
 class NearestService final : public BaseService
@@ -28,8 +24,6 @@ class NearestService final : public BaseService
 
     unsigned GetVersion() final override { return 1; }
 };
-} // namespace service
-} // namespace server
 } // namespace osrm
 
 #endif
diff --git a/include/server/service/route_service.hpp b/include/server/service/route_service.hpp
index 033bfbd61..642c4a827 100644
--- a/include/server/service/route_service.hpp
+++ b/include/server/service/route_service.hpp
@@ -10,11 +10,7 @@
 #include <string>
 #include <vector>
 
-namespace osrm
-{
-namespace server
-{
-namespace service
+namespace osrm::server::service
 {
 
 class RouteService final : public BaseService
@@ -28,8 +24,6 @@ class RouteService final : public BaseService
 
     unsigned GetVersion() final override { return 1; }
 };
-} // namespace service
-} // namespace server
 } // namespace osrm
 
 #endif
diff --git a/include/server/service/table_service.hpp b/include/server/service/table_service.hpp
index 3eb4c72e6..e23bbf547 100644
--- a/include/server/service/table_service.hpp
+++ b/include/server/service/table_service.hpp
@@ -10,11 +10,7 @@
 #include <string>
 #include <vector>
 
-namespace osrm
-{
-namespace server
-{
-namespace service
+namespace osrm::server::service
 {
 
 class TableService final : public BaseService
@@ -28,8 +24,6 @@ class TableService final : public BaseService
 
     unsigned GetVersion() final override { return 1; }
 };
-} // namespace service
-} // namespace server
 } // namespace osrm
 
 #endif
diff --git a/include/server/service/tile_service.hpp b/include/server/service/tile_service.hpp
index 4693c9739..a4d9e6fe2 100644
--- a/include/server/service/tile_service.hpp
+++ b/include/server/service/tile_service.hpp
@@ -10,11 +10,7 @@
 #include <string>
 #include <vector>
 
-namespace osrm
-{
-namespace server
-{
-namespace service
+namespace osrm::server::service
 {
 
 class TileService final : public BaseService
@@ -28,8 +24,6 @@ class TileService final : public BaseService
 
     unsigned GetVersion() final override { return 1; }
 };
-} // namespace service
-} // namespace server
 } // namespace osrm
 
 #endif
diff --git a/include/server/service/trip_service.hpp b/include/server/service/trip_service.hpp
index 0180aa8e4..605523376 100644
--- a/include/server/service/trip_service.hpp
+++ b/include/server/service/trip_service.hpp
@@ -10,11 +10,7 @@
 #include <string>
 #include <vector>
 
-namespace osrm
-{
-namespace server
-{
-namespace service
+namespace osrm::server::service
 {
 
 class TripService final : public BaseService
@@ -28,8 +24,6 @@ class TripService final : public BaseService
 
     unsigned GetVersion() final override { return 1; }
 };
-} // namespace service
-} // namespace server
 } // namespace osrm
 
 #endif
diff --git a/include/server/service/utils.hpp b/include/server/service/utils.hpp
index fc76d0d14..7d008d1a8 100644
--- a/include/server/service/utils.hpp
+++ b/include/server/service/utils.hpp
@@ -1,10 +1,6 @@
 #include <boost/format.hpp>
 
-namespace osrm
-{
-namespace server
-{
-namespace service
+namespace osrm::server::service
 {
 
 const constexpr char PARAMETER_SIZE_MISMATCH_MSG[] =
@@ -24,6 +20,4 @@ bool constrainParamSize(const char *msg_template,
     }
     return false;
 }
-} // namespace service
-} // namespace server
 } // namespace osrm
diff --git a/include/server/service_handler.hpp b/include/server/service_handler.hpp
index 2b62b0687..fe3557f8d 100644
--- a/include/server/service_handler.hpp
+++ b/include/server/service_handler.hpp
@@ -10,12 +10,9 @@
 
 namespace osrm
 {
-namespace util
-{
-namespace json
+namespace util::json
 {
 struct Object;
-}
 } // namespace util
 namespace server
 {
diff --git a/include/storage/block.hpp b/include/storage/block.hpp
index d8ba76859..4482b2453 100644
--- a/include/storage/block.hpp
+++ b/include/storage/block.hpp
@@ -7,9 +7,7 @@
 #include <string>
 #include <tuple>
 
-namespace osrm
-{
-namespace storage
+namespace osrm::storage
 {
 
 struct Block
@@ -37,7 +35,6 @@ template <typename T> Block make_block(uint64_t num_entries)
     static_assert(sizeof(T) % alignof(T) == 0, "aligned T* can't be used as an array pointer");
     return Block{num_entries, sizeof(T) * num_entries, 0};
 }
-} // namespace storage
 } // namespace osrm
 
 #endif
diff --git a/include/storage/io.hpp b/include/storage/io.hpp
index dc681c2fe..782deb186 100644
--- a/include/storage/io.hpp
+++ b/include/storage/io.hpp
@@ -21,11 +21,7 @@
 #include <tuple>
 #include <type_traits>
 
-namespace osrm
-{
-namespace storage
-{
-namespace io
+namespace osrm::storage::io
 {
 
 class FileReader
@@ -388,8 +384,6 @@ class BufferWriter
   private:
     std::ostringstream output_stream;
 };
-} // namespace io
-} // namespace storage
 } // namespace osrm
 
 #endif
diff --git a/include/storage/io_config.hpp b/include/storage/io_config.hpp
index 831382df7..58847c60a 100644
--- a/include/storage/io_config.hpp
+++ b/include/storage/io_config.hpp
@@ -9,9 +9,7 @@
 #include <boost/filesystem/path.hpp>
 #include <string>
 
-namespace osrm
-{
-namespace storage
+namespace osrm::storage
 {
 struct IOConfig
 {
@@ -81,7 +79,6 @@ struct IOConfig
     std::vector<boost::filesystem::path> optional_input_files;
     std::vector<boost::filesystem::path> output_files;
 };
-} // namespace storage
 } // namespace osrm
 
 #endif
diff --git a/include/storage/io_fwd.hpp b/include/storage/io_fwd.hpp
index 8bfef5728..685864604 100644
--- a/include/storage/io_fwd.hpp
+++ b/include/storage/io_fwd.hpp
@@ -1,18 +1,12 @@
 #ifndef OSRM_STORAGE_IO_FWD_HPP_
 #define OSRM_STORAGE_IO_FWD_HPP_
 
-namespace osrm
-{
-namespace storage
-{
-namespace io
+namespace osrm::storage::io
 {
 
 class FileReader;
 class FileWriter;
 
-} // namespace io
-} // namespace storage
 } // namespace osrm
 
 #endif
diff --git a/include/storage/serialization.hpp b/include/storage/serialization.hpp
index 60532d691..800dc2196 100644
--- a/include/storage/serialization.hpp
+++ b/include/storage/serialization.hpp
@@ -17,11 +17,7 @@
 #include <cstdint>
 #include <tuple>
 
-namespace osrm
-{
-namespace storage
-{
-namespace serialization
+namespace osrm::storage::serialization
 {
 
 namespace detail
@@ -268,8 +264,6 @@ inline void write(io::BufferWriter &writer, const BaseDataLayout &layout)
 {
     write(writer, layout.blocks);
 }
-} // namespace serialization
-} // namespace storage
 } // namespace osrm
 
 #endif
diff --git a/include/storage/shared_data_index.hpp b/include/storage/shared_data_index.hpp
index 8cafc572f..9cfb716d5 100644
--- a/include/storage/shared_data_index.hpp
+++ b/include/storage/shared_data_index.hpp
@@ -8,9 +8,7 @@
 #include <type_traits>
 #include <unordered_map>
 
-namespace osrm
-{
-namespace storage
+namespace osrm::storage
 {
 
 // This class wraps one or more shared memory regions with the associated data layout
@@ -95,7 +93,6 @@ class SharedDataIndex
     std::vector<AllocatedRegion> regions;
     std::unordered_map<std::string, std::uint32_t> block_to_region;
 };
-} // namespace storage
 } // namespace osrm
 
 #endif
diff --git a/include/storage/shared_datatype.hpp b/include/storage/shared_datatype.hpp
index 2ee55f40d..a6f719456 100644
--- a/include/storage/shared_datatype.hpp
+++ b/include/storage/shared_datatype.hpp
@@ -15,9 +15,7 @@
 #include <numeric>
 #include <unordered_set>
 
-namespace osrm
-{
-namespace storage
+namespace osrm::storage
 {
 
 class BaseDataLayout;
@@ -298,7 +296,6 @@ struct SharedRegionRegister
     std::array<SharedRegion, MAX_SHARED_REGIONS> regions;
     std::array<bool, MAX_SHM_KEYS> shm_key_in_use;
 };
-} // namespace storage
 } // namespace osrm
 
 #endif /* SHARED_DATA_TYPE_HPP */
diff --git a/include/storage/shared_memory.hpp b/include/storage/shared_memory.hpp
index 3b558238d..cc4429046 100644
--- a/include/storage/shared_memory.hpp
+++ b/include/storage/shared_memory.hpp
@@ -27,9 +27,7 @@
 
 #include "storage/shared_memory_ownership.hpp"
 
-namespace osrm
-{
-namespace storage
+namespace osrm::storage
 {
 
 struct OSRMLockFile
@@ -311,7 +309,6 @@ std::unique_ptr<SharedMemory> makeSharedMemory(const IdentifierT &id, const uint
         throw util::exception(e.what() + SOURCE_REF);
     }
 }
-} // namespace storage
 } // namespace osrm
 
 #endif // SHARED_MEMORY_HPP
diff --git a/include/storage/shared_memory_ownership.hpp b/include/storage/shared_memory_ownership.hpp
index 5c3074e5e..f6d9793a6 100644
--- a/include/storage/shared_memory_ownership.hpp
+++ b/include/storage/shared_memory_ownership.hpp
@@ -1,9 +1,7 @@
 #ifndef SHARED_MEMORY_OWNERSHIP_HPP
 #define SHARED_MEMORY_OWNERSHIP_HPP
 
-namespace osrm
-{
-namespace storage
+namespace osrm::storage
 {
 
 enum class Ownership
@@ -12,7 +10,6 @@ enum class Ownership
     View,
     External
 };
-} // namespace storage
 } // namespace osrm
 
 #endif // SHARED_MEMORY_OWNERSHIP_HPP
diff --git a/include/storage/shared_monitor.hpp b/include/storage/shared_monitor.hpp
index 5a8d255d9..25516097a 100644
--- a/include/storage/shared_monitor.hpp
+++ b/include/storage/shared_monitor.hpp
@@ -16,9 +16,7 @@
 // #define USE_BOOST_INTERPROCESS_CONDITION 1
 #endif
 
-namespace osrm
-{
-namespace storage
+namespace osrm::storage
 {
 
 namespace
@@ -234,7 +232,6 @@ template <typename Data> struct SharedMonitor
     bi::shared_memory_object shmem;
     bi::mapped_region region;
 };
-} // namespace storage
 } // namespace osrm
 
 #undef USE_BOOST_INTERPROCESS_CONDITION
diff --git a/include/storage/storage.hpp b/include/storage/storage.hpp
index 8c8b974f6..c799e1429 100644
--- a/include/storage/storage.hpp
+++ b/include/storage/storage.hpp
@@ -37,9 +37,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <string>
 #include <vector>
 
-namespace osrm
-{
-namespace storage
+namespace osrm::storage
 {
 
 void populateLayoutFromFile(const boost::filesystem::path &path, storage::BaseDataLayout &layout);
@@ -61,7 +59,6 @@ class Storage
   private:
     StorageConfig config;
 };
-} // namespace storage
 } // namespace osrm
 
 #endif
diff --git a/include/storage/storage_config.hpp b/include/storage/storage_config.hpp
index 581b45e32..65f21fdf3 100644
--- a/include/storage/storage_config.hpp
+++ b/include/storage/storage_config.hpp
@@ -32,9 +32,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include "storage/io_config.hpp"
 
-namespace osrm
-{
-namespace storage
+namespace osrm::storage
 {
 
 /**
@@ -75,7 +73,6 @@ struct StorageConfig final : IOConfig
     {
     }
 };
-} // namespace storage
 } // namespace osrm
 
 #endif
diff --git a/include/storage/tar.hpp b/include/storage/tar.hpp
index a13893589..18ef499b6 100644
--- a/include/storage/tar.hpp
+++ b/include/storage/tar.hpp
@@ -14,11 +14,7 @@ extern "C"
 #include "microtar.h"
 }
 
-namespace osrm
-{
-namespace storage
-{
-namespace tar
+namespace osrm::storage::tar
 {
 namespace detail
 {
@@ -312,8 +308,6 @@ class FileWriter
     boost::filesystem::path path;
     mtar_t handle;
 };
-} // namespace tar
-} // namespace storage
 } // namespace osrm
 
 #endif
diff --git a/include/storage/tar_fwd.hpp b/include/storage/tar_fwd.hpp
index b8503e003..9ca199d99 100644
--- a/include/storage/tar_fwd.hpp
+++ b/include/storage/tar_fwd.hpp
@@ -1,18 +1,12 @@
 #ifndef OSRM_STORAGE_TAR_FWD_HPP_
 #define OSRM_STORAGE_TAR_FWD_HPP_
 
-namespace osrm
-{
-namespace storage
-{
-namespace tar
+namespace osrm::storage::tar
 {
 
 class FileReader;
 class FileWriter;
 
-} // namespace tar
-} // namespace storage
 } // namespace osrm
 
 #endif
diff --git a/include/storage/view_factory.hpp b/include/storage/view_factory.hpp
index 80db376bf..7b994bbec 100644
--- a/include/storage/view_factory.hpp
+++ b/include/storage/view_factory.hpp
@@ -36,9 +36,7 @@
 #include "util/vector_view.hpp"
 
 #include "util/filtered_graph.hpp"
-namespace osrm
-{
-namespace storage
+namespace osrm::storage
 {
 
 template <typename T>
@@ -364,7 +362,6 @@ inline auto make_filtered_graph_view(const SharedDataIndex &index,
 
     return util::FilteredGraphView<contractor::QueryGraphView>({node_list, edge_list}, edge_filter);
 }
-} // namespace storage
 } // namespace osrm
 
 #endif
diff --git a/include/updater/csv_file_parser.hpp b/include/updater/csv_file_parser.hpp
index 92c3dcabb..819eba6e4 100644
--- a/include/updater/csv_file_parser.hpp
+++ b/include/updater/csv_file_parser.hpp
@@ -21,9 +21,7 @@
 #include <stdexcept>
 #include <vector>
 
-namespace osrm
-{
-namespace updater
+namespace osrm::updater
 {
 
 // Functor to parse a list of CSV files using "key,value,comment" grammar.
@@ -138,7 +136,6 @@ template <typename Key, typename Value> struct CSVFilesParser
     const KeyRule key_rule;
     const ValueRule value_rule;
 };
-} // namespace updater
 } // namespace osrm
 
 #endif
diff --git a/include/updater/csv_source.hpp b/include/updater/csv_source.hpp
index 8fa00941a..f105537fd 100644
--- a/include/updater/csv_source.hpp
+++ b/include/updater/csv_source.hpp
@@ -3,16 +3,10 @@
 
 #include "updater/source.hpp"
 
-namespace osrm
-{
-namespace updater
-{
-namespace csv
+namespace osrm::updater::csv
 {
 SegmentLookupTable readSegmentValues(const std::vector<std::string> &paths);
 TurnLookupTable readTurnValues(const std::vector<std::string> &paths);
-} // namespace csv
-} // namespace updater
 } // namespace osrm
 
 #endif
diff --git a/include/updater/source.hpp b/include/updater/source.hpp
index b00d402c9..61e7d1eed 100644
--- a/include/updater/source.hpp
+++ b/include/updater/source.hpp
@@ -7,9 +7,7 @@
 
 #include <vector>
 
-namespace osrm
-{
-namespace updater
+namespace osrm::updater
 {
 
 template <typename Key, typename Value> struct LookupTable
@@ -88,7 +86,6 @@ struct PenaltySource final
 
 using SegmentLookupTable = LookupTable<Segment, SpeedSource>;
 using TurnLookupTable = LookupTable<Turn, PenaltySource>;
-} // namespace updater
 } // namespace osrm
 
 #endif
diff --git a/include/updater/updater.hpp b/include/updater/updater.hpp
index e5610c6bd..55a1ebfb7 100644
--- a/include/updater/updater.hpp
+++ b/include/updater/updater.hpp
@@ -8,9 +8,7 @@
 #include <chrono>
 #include <vector>
 
-namespace osrm
-{
-namespace updater
+namespace osrm::updater
 {
 class Updater
 {
@@ -37,7 +35,6 @@ class Updater
   private:
     UpdaterConfig config;
 };
-} // namespace updater
 } // namespace osrm
 
 #endif
diff --git a/include/updater/updater_config.hpp b/include/updater/updater_config.hpp
index 3fc3e5b71..65467a6aa 100644
--- a/include/updater/updater_config.hpp
+++ b/include/updater/updater_config.hpp
@@ -36,9 +36,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include "storage/io_config.hpp"
 #include "storage/storage_config.hpp"
 
-namespace osrm
-{
-namespace updater
+namespace osrm::updater
 {
 
 struct UpdaterConfig final : storage::IOConfig
@@ -73,7 +71,6 @@ struct UpdaterConfig final : storage::IOConfig
     std::vector<std::string> turn_penalty_lookup_paths;
     std::string tz_file_path;
 };
-} // namespace updater
 } // namespace osrm
 
 #endif // EXTRACTOR_OPTIONS_HPP
diff --git a/include/util/bearing.hpp b/include/util/bearing.hpp
index c046bf417..f3a663aa6 100644
--- a/include/util/bearing.hpp
+++ b/include/util/bearing.hpp
@@ -6,9 +6,7 @@
 #include <cmath>
 #include <string>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 namespace bearing
 {
@@ -144,7 +142,6 @@ inline double restrictAngleToValidRange(const double angle)
         return angle;
 }
 
-} // namespace util
 } // namespace osrm
 
 #endif // BEARING_HPP
diff --git a/include/util/bit_range.hpp b/include/util/bit_range.hpp
index 876c46a2d..5385a2fbb 100644
--- a/include/util/bit_range.hpp
+++ b/include/util/bit_range.hpp
@@ -6,9 +6,7 @@
 #include <boost/iterator/iterator_facade.hpp>
 #include <boost/range/iterator_range.hpp>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 namespace detail
@@ -92,7 +90,6 @@ template <typename T> auto makeBitRange(const T value)
 {
     return boost::make_iterator_range(BitIterator<T>{value}, BitIterator<T>{});
 }
-} // namespace util
 } // namespace osrm
 
 #endif
diff --git a/include/util/concurrent_id_map.hpp b/include/util/concurrent_id_map.hpp
index f5fbb4374..bd265255e 100644
--- a/include/util/concurrent_id_map.hpp
+++ b/include/util/concurrent_id_map.hpp
@@ -7,9 +7,7 @@
 
 #include <unordered_map>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 /**
@@ -74,7 +72,6 @@ struct ConcurrentIDMap
     }
 };
 
-} // namespace util
 } // namespace osrm
 
 #endif // CONCURRENT_ID_MAP_HPP
diff --git a/include/util/conditional_restrictions.hpp b/include/util/conditional_restrictions.hpp
index e18379698..1d1614471 100644
--- a/include/util/conditional_restrictions.hpp
+++ b/include/util/conditional_restrictions.hpp
@@ -4,9 +4,7 @@
 #include <string>
 #include <vector>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 // Helper functions for OSM conditional restrictions
@@ -21,7 +19,6 @@ struct ConditionalRestriction
 
 std::vector<ConditionalRestriction> ParseConditionalRestrictions(const std::string &str);
 
-} // namespace util
 } // namespace osrm
 
 #endif // OSRM_CONDITIONAL_RESTRICTIONS_HPP
diff --git a/include/util/connectivity_checksum.hpp b/include/util/connectivity_checksum.hpp
index 25893a8d2..38819aba1 100644
--- a/include/util/connectivity_checksum.hpp
+++ b/include/util/connectivity_checksum.hpp
@@ -9,9 +9,7 @@
 #include <climits>
 #include <cstdint>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 struct ConnectivityChecksum
@@ -84,7 +82,6 @@ struct ConnectivityChecksum
     std::size_t byte_number;
     unsigned char bit_number;
 };
-} // namespace util
 } // namespace osrm
 
 #endif
diff --git a/include/util/coordinate_calculation.hpp b/include/util/coordinate_calculation.hpp
index 959a74107..d51c87795 100644
--- a/include/util/coordinate_calculation.hpp
+++ b/include/util/coordinate_calculation.hpp
@@ -12,11 +12,7 @@
 #include <utility>
 #include <vector>
 
-namespace osrm
-{
-namespace util
-{
-namespace coordinate_calculation
+namespace osrm::util::coordinate_calculation
 {
 
 namespace detail
@@ -377,8 +373,6 @@ bool areParallel(const iterator_type lhs_begin,
 
 double computeArea(const std::vector<Coordinate> &polygon);
 
-} // namespace coordinate_calculation
-} // namespace util
 } // namespace osrm
 
 #endif // COORDINATE_CALCULATION
diff --git a/include/util/deallocating_vector.hpp b/include/util/deallocating_vector.hpp
index 484a51b1b..8700ff17d 100644
--- a/include/util/deallocating_vector.hpp
+++ b/include/util/deallocating_vector.hpp
@@ -11,9 +11,7 @@
 #include <utility>
 #include <vector>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 template <typename ElementT> struct ConstDeallocatingVectorIteratorState
 {
@@ -348,7 +346,6 @@ template <typename T> void swap(DeallocatingVector<T> &lhs, DeallocatingVector<T
 {
     lhs.swap(rhs);
 }
-} // namespace util
 } // namespace osrm
 
 #endif /* DEALLOCATING_VECTOR_HPP */
diff --git a/include/util/debug.hpp b/include/util/debug.hpp
index d318a7249..9db80e025 100644
--- a/include/util/debug.hpp
+++ b/include/util/debug.hpp
@@ -29,9 +29,7 @@ inline std::ostream &operator<<(std::ostream &out, const Coordinate &coordinate)
 }
 } // namespace util
 
-namespace engine
-{
-namespace guidance
+namespace engine::guidance
 {
 inline std::ostream &operator<<(std::ostream &out, const RouteStep &step)
 {
@@ -62,7 +60,6 @@ inline std::ostream &operator<<(std::ostream &out, const RouteStep &step)
 
     return out;
 }
-} // namespace guidance
 } // namespace engine
 
 namespace guidance
diff --git a/include/util/dist_table_wrapper.hpp b/include/util/dist_table_wrapper.hpp
index 5ea2de4bb..33a4fc59d 100644
--- a/include/util/dist_table_wrapper.hpp
+++ b/include/util/dist_table_wrapper.hpp
@@ -9,9 +9,7 @@
 #include <utility>
 #include <vector>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 // This Wrapper provides an easier access to a distance table that is given as an linear vector
@@ -77,7 +75,6 @@ template <typename T> class DistTableWrapper
     std::vector<T> table_;
     const std::size_t number_of_nodes_;
 };
-} // namespace util
 } // namespace osrm
 
 #endif // DIST_TABLE_WRAPPER_H
diff --git a/include/util/dynamic_graph.hpp b/include/util/dynamic_graph.hpp
index 5cee5b3e0..e0bce6d7f 100644
--- a/include/util/dynamic_graph.hpp
+++ b/include/util/dynamic_graph.hpp
@@ -18,9 +18,7 @@
 #include <tuple>
 #include <vector>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 namespace detail
 {
@@ -468,7 +466,6 @@ template <typename EdgeDataT> class DynamicGraph
     std::vector<Node> node_array;
     DeallocatingVector<Edge> edge_list;
 };
-} // namespace util
 } // namespace osrm
 
 #endif // DYNAMICGRAPH_HPP
diff --git a/include/util/exception.hpp b/include/util/exception.hpp
index 3dee59ea4..89b1d776b 100644
--- a/include/util/exception.hpp
+++ b/include/util/exception.hpp
@@ -37,9 +37,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include "osrm/error_codes.hpp"
 #include <boost/format.hpp>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 class exception : public std::exception
@@ -124,7 +122,6 @@ class RuntimeError : public exception
         return result;
     }
 };
-} // namespace util
 } // namespace osrm
 
 #endif /* OSRM_EXCEPTION_HPP */
diff --git a/include/util/exclude_flag.hpp b/include/util/exclude_flag.hpp
index 373faeb90..0692f0b66 100644
--- a/include/util/exclude_flag.hpp
+++ b/include/util/exclude_flag.hpp
@@ -4,9 +4,7 @@
 #include "extractor/node_data_container.hpp"
 #include "extractor/profile_properties.hpp"
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 inline std::vector<std::vector<bool>>
@@ -29,7 +27,6 @@ excludeFlagsToNodeFilter(const NodeID number_of_nodes,
     }
     return filters;
 }
-} // namespace util
 } // namespace osrm
 
 #endif
diff --git a/include/util/filtered_graph.hpp b/include/util/filtered_graph.hpp
index 55c2d047e..fe5b11feb 100644
--- a/include/util/filtered_graph.hpp
+++ b/include/util/filtered_graph.hpp
@@ -8,9 +8,7 @@
 #include "util/static_graph.hpp"
 #include "util/vector_view.hpp"
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 namespace detail
 {
@@ -159,7 +157,6 @@ template <typename GraphT>
 using FilteredGraphContainer = detail::FilteredGraphImpl<GraphT, storage::Ownership::Container>;
 template <typename GraphT>
 using FilteredGraphView = detail::FilteredGraphImpl<GraphT, storage::Ownership::View>;
-} // namespace util
 } // namespace osrm
 
 #endif
diff --git a/include/util/filtered_integer_range.hpp b/include/util/filtered_integer_range.hpp
index be95cea27..2d39404c2 100644
--- a/include/util/filtered_integer_range.hpp
+++ b/include/util/filtered_integer_range.hpp
@@ -8,9 +8,7 @@
 
 #include <cstdint>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 // This implements a single-pass integer range.
@@ -94,7 +92,6 @@ filtered_range<Integer, Filter> filtered_irange(
 {
     return filtered_range<Integer, Filter>(first, last, filter);
 }
-} // namespace util
 } // namespace osrm
 
 #endif // INTEGER_RANGE_HPP
diff --git a/include/util/fingerprint.hpp b/include/util/fingerprint.hpp
index 14a9b4b2b..9f9fcd89f 100644
--- a/include/util/fingerprint.hpp
+++ b/include/util/fingerprint.hpp
@@ -6,9 +6,7 @@
 #include <cstdint>
 #include <type_traits>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 // implements a singleton, i.e. there is one and only one conviguration object
@@ -36,7 +34,6 @@ struct FingerPrint
 static_assert(sizeof(FingerPrint) == 8, "FingerPrint has unexpected size");
 static_assert(std::is_trivial<FingerPrint>::value, "FingerPrint needs to be trivial.");
 static_assert(std::is_pod<FingerPrint>::value, "FingerPrint needs to be a POD.");
-} // namespace util
 } // namespace osrm
 
 #endif /* FingerPrint_H */
diff --git a/include/util/for_each_indexed.hpp b/include/util/for_each_indexed.hpp
index 86655416b..cf467d0e9 100644
--- a/include/util/for_each_indexed.hpp
+++ b/include/util/for_each_indexed.hpp
@@ -5,9 +5,7 @@
 #include <numeric>
 #include <utility>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 template <typename ForwardIterator, typename Function>
@@ -25,7 +23,6 @@ void for_each_indexed(ContainerT &container, Function function)
     for_each_indexed(std::begin(container), std::end(container), function);
 }
 
-} // namespace util
 } // namespace osrm
 
 #endif /* FOR_EACH_INDEXED_HPP */
diff --git a/include/util/for_each_pair.hpp b/include/util/for_each_pair.hpp
index bd6c4dd39..58f9425c2 100644
--- a/include/util/for_each_pair.hpp
+++ b/include/util/for_each_pair.hpp
@@ -5,9 +5,7 @@
 #include <numeric>
 #include <utility>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 // TODO: check why this is not an option here:
@@ -39,7 +37,6 @@ void for_each_pair(ContainerT &container, Function &&function)
     for_each_pair(begin(container), end(container), std::forward<Function>(function));
 }
 
-} // namespace util
 } // namespace osrm
 
 #endif /* FOR_EACH_PAIR_HPP */
diff --git a/include/util/for_each_range.hpp b/include/util/for_each_range.hpp
index 6df81b4da..7200f009f 100644
--- a/include/util/for_each_range.hpp
+++ b/include/util/for_each_range.hpp
@@ -1,9 +1,7 @@
 #ifndef OSRM_UTIL_FOR_EACH_RANGE_HPP
 #define OSRM_UTIL_FOR_EACH_RANGE_HPP
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 template <typename Iter, typename Func> void for_each_range(Iter begin, Iter end, Func f)
@@ -20,7 +18,6 @@ template <typename Iter, typename Func> void for_each_range(Iter begin, Iter end
         f(begin_range, iter);
     }
 }
-} // namespace util
 } // namespace osrm
 
 #endif
diff --git a/include/util/geojson_debug_logger.hpp b/include/util/geojson_debug_logger.hpp
index 4a9905651..d66b87271 100644
--- a/include/util/geojson_debug_logger.hpp
+++ b/include/util/geojson_debug_logger.hpp
@@ -11,9 +11,7 @@
 #include "util/json_renderer.hpp"
 #include "util/log.hpp"
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 // in case we want to do scenario-based logging, we can specify a dedicated logging scenario to be
@@ -183,7 +181,6 @@ std::ofstream GeojsonLogger<geojson_conversion_policy, scenario>::ofs;
 template <class geojson_conversion_policy, LoggingScenario scenario>
 geojson_conversion_policy *GeojsonLogger<geojson_conversion_policy, scenario>::policy;
 
-} // namespace util
 } // namespace osrm
 
 #endif /* OSRM_GEOJSON_DEBUG_LOGGER_HPP */
diff --git a/include/util/geojson_debug_policies.hpp b/include/util/geojson_debug_policies.hpp
index a38bae353..cc7ed16de 100644
--- a/include/util/geojson_debug_policies.hpp
+++ b/include/util/geojson_debug_policies.hpp
@@ -11,9 +11,7 @@
 
 #include <boost/optional.hpp>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 struct NodeIdVectorToLineString
@@ -52,7 +50,6 @@ struct CoordinateVectorToMultiPoint
                                   const boost::optional<json::Object> &properties = {}) const;
 };
 
-} /* namespace util */
 } /* namespace osrm */
 
 #endif /* OSRM_GEOJSON_DEBUG_POLICIES */
diff --git a/include/util/geojson_debug_policy_toolkit.hpp b/include/util/geojson_debug_policy_toolkit.hpp
index 3d27c35c6..98d3cc04f 100644
--- a/include/util/geojson_debug_policy_toolkit.hpp
+++ b/include/util/geojson_debug_policy_toolkit.hpp
@@ -10,9 +10,7 @@
 
 #include <boost/optional.hpp>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 enum GeojsonStyleSize
@@ -109,7 +107,6 @@ inline util::json::Array makeJsonArray(const std::vector<util::Coordinate> &inpu
                    CoordinateToJsonArray());
     return coordinates;
 }
-} // namespace util
 } // namespace osrm
 
 #endif /* OSRM_GEOJSON_DEBUG_POLICY_TOOLKIT_HPP */
diff --git a/include/util/geojson_validation.hpp b/include/util/geojson_validation.hpp
index 8482395be..a808d35a1 100644
--- a/include/util/geojson_validation.hpp
+++ b/include/util/geojson_validation.hpp
@@ -6,9 +6,7 @@
 
 #include "rapidjson/document.h"
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 inline void validateCoordinate(const rapidjson::Value &coordinate)
@@ -85,6 +83,5 @@ inline void validateFeature(const rapidjson::Value &feature)
         }
     }
 }
-} // namespace util
 } // namespace osrm
 #endif // OSRM_GEOJSON_VALIDATION_HPP
diff --git a/include/util/graph_traits.hpp b/include/util/graph_traits.hpp
index 31edfadf1..3df91dea2 100644
--- a/include/util/graph_traits.hpp
+++ b/include/util/graph_traits.hpp
@@ -3,12 +3,7 @@
 
 #include <type_traits>
 
-namespace osrm
-{
-namespace util
-{
-
-namespace traits
+namespace osrm::util::traits
 {
 
 // Introspection for an arbitrary .data member attribute
@@ -49,8 +44,6 @@ struct HasFirstEdgeMember<T, decltype((void)(sizeof(std::declval<T>().first_edge
 {
 };
 
-} // namespace traits
-} // namespace util
 } // namespace osrm
 
 #endif // STATIC_GRAPH_TRAITS_HPP
diff --git a/include/util/graph_utils.hpp b/include/util/graph_utils.hpp
index bb0bebf66..847cc26a2 100644
--- a/include/util/graph_utils.hpp
+++ b/include/util/graph_utils.hpp
@@ -6,9 +6,7 @@
 #include <boost/assert.hpp>
 #include <vector>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 /// This function checks if the graph (consisting of directed edges) is undirected
@@ -96,7 +94,6 @@ std::vector<OutputEdgeT> directedEdgesFromCompressed(const std::vector<InputEdge
 
     return output_edge_list;
 }
-} // namespace util
 } // namespace osrm
 
 #endif
diff --git a/include/util/group_by.hpp b/include/util/group_by.hpp
index 22473729e..71729c75c 100644
--- a/include/util/group_by.hpp
+++ b/include/util/group_by.hpp
@@ -4,9 +4,7 @@
 #include <algorithm>
 #include <utility>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 // Runs fn on consecutive items in sub-ranges determined by pred.
@@ -34,7 +32,6 @@ Fn group_by(Iter first, Iter last, Pred pred, Fn fn)
     return fn;
 }
 
-} // namespace util
 } // namespace osrm
 
 #endif
diff --git a/include/util/guidance/bearing_class.hpp b/include/util/guidance/bearing_class.hpp
index 57e364190..51c1d3d6f 100644
--- a/include/util/guidance/bearing_class.hpp
+++ b/include/util/guidance/bearing_class.hpp
@@ -10,15 +10,9 @@
 
 #include "util/typedefs.hpp"
 
-namespace osrm
-{
-namespace util
-{
-namespace guidance
+namespace osrm::util::guidance
 {
 class BearingClass;
-} // namespace guidance
-} // namespace util
 } // namespace osrm
 
 namespace std
@@ -29,11 +23,7 @@ template <> struct hash<::osrm::util::guidance::BearingClass>
 };
 } // namespace std
 
-namespace osrm
-{
-namespace util
-{
-namespace guidance
+namespace osrm::util::guidance
 {
 
 class BearingClass
@@ -64,8 +54,6 @@ class BearingClass
     friend std::size_t std::hash<BearingClass>::operator()(const BearingClass &) const;
 };
 
-} // namespace guidance
-} // namespace util
 } // namespace osrm
 
 // make Bearing Class hasbable
diff --git a/include/util/guidance/entry_class.hpp b/include/util/guidance/entry_class.hpp
index 6d6838e27..c6d4db2cc 100644
--- a/include/util/guidance/entry_class.hpp
+++ b/include/util/guidance/entry_class.hpp
@@ -8,15 +8,9 @@
 
 #include <bitset>
 
-namespace osrm
-{
-namespace util
-{
-namespace guidance
+namespace osrm::util::guidance
 {
 class EntryClass;
-} // namespace guidance
-} // namespace util
 } // namespace osrm
 
 namespace std
@@ -29,9 +23,7 @@ template <> struct hash<::osrm::util::guidance::EntryClass>
 
 namespace osrm
 {
-namespace util
-{
-namespace guidance
+namespace util::guidance
 {
 
 class EntryClass
@@ -71,7 +63,6 @@ static_assert(std::is_trivially_copyable<EntryClass>::value,
               "requires trivially copyable type");
 #endif
 
-} // namespace guidance
 } // namespace util
 
 constexpr const util::guidance::EntryClass EMPTY_ENTRY_CLASS{};
diff --git a/include/util/guidance/name_announcements.hpp b/include/util/guidance/name_announcements.hpp
index 32202974d..79a1a2b7f 100644
--- a/include/util/guidance/name_announcements.hpp
+++ b/include/util/guidance/name_announcements.hpp
@@ -18,11 +18,7 @@
 #include <boost/algorithm/string.hpp>
 #include <boost/algorithm/string/predicate.hpp>
 
-namespace osrm
-{
-namespace util
-{
-namespace guidance
+namespace osrm::util::guidance
 {
 // Name Change Logic
 // Used both during Extraction as well as during Post-Processing
@@ -240,8 +236,6 @@ inline bool requiresNameAnnounced(const NameID from_name_id,
                                      suffix_table);
 }
 
-} // namespace guidance
-} // namespace util
 } // namespace osrm
 
 #endif /* OSRM_UTIL_GUIDANCE_NAME_ANNOUNCEMENT_HPP_ */
diff --git a/include/util/guidance/turn_lanes.hpp b/include/util/guidance/turn_lanes.hpp
index 542007f6e..c09035078 100644
--- a/include/util/guidance/turn_lanes.hpp
+++ b/include/util/guidance/turn_lanes.hpp
@@ -12,16 +12,10 @@
 
 #include <boost/functional/hash.hpp>
 
-namespace osrm
-{
-namespace util
-{
-namespace guidance
+namespace osrm::util::guidance
 {
 class LaneTuple;
 class LaneTupleIdPair;
-} // namespace guidance
-} // namespace util
 } // namespace osrm
 
 namespace std
@@ -37,11 +31,7 @@ template <> struct hash<::osrm::util::guidance::LaneTupleIdPair>
 };
 } // namespace std
 
-namespace osrm
-{
-namespace util
-{
-namespace guidance
+namespace osrm::util::guidance
 {
 
 // The mapping of turn lanes can be done two values. We describe every turn by the number of
@@ -100,8 +90,6 @@ class LaneTupleIdPair
 
 using LaneDataIdMap = ConcurrentIDMap<LaneTupleIdPair, LaneDataID, boost::hash<LaneTupleIdPair>>;
 
-} // namespace guidance
-} // namespace util
 } // namespace osrm
 
 #endif /* OSRM_UTIL_GUIDANCE_TURN_LANES_HPP */
diff --git a/include/util/hilbert_value.hpp b/include/util/hilbert_value.hpp
index 7521cbd92..46807b1af 100644
--- a/include/util/hilbert_value.hpp
+++ b/include/util/hilbert_value.hpp
@@ -6,9 +6,7 @@
 #include <climits>
 #include <cstdint>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 // Transform x and y to Hilbert SFC linear coordinate
@@ -69,7 +67,6 @@ inline std::uint64_t GetHilbertCode(const Coordinate &coordinate)
                             static_cast<std::int32_t>(90 * COORDINATE_PRECISION);
     return HilbertToLinear(x, y);
 }
-} // namespace util
 } // namespace osrm
 
 #endif /* HILBERT_VALUE_HPP */
diff --git a/include/util/indexed_data.hpp b/include/util/indexed_data.hpp
index 712597784..92cdc5875 100644
--- a/include/util/indexed_data.hpp
+++ b/include/util/indexed_data.hpp
@@ -16,9 +16,7 @@
 #include <string_view>
 #include <type_traits>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 namespace detail
 {
@@ -389,6 +387,5 @@ template <typename GroupBlockPolicy>
 using IndexedData = detail::IndexedDataImpl<GroupBlockPolicy, storage::Ownership::Container>;
 template <typename GroupBlockPolicy>
 using IndexedDataView = detail::IndexedDataImpl<GroupBlockPolicy, storage::Ownership::View>;
-} // namespace util
 } // namespace osrm
 #endif // OSRM_INDEXED_DATA_HPP
diff --git a/include/util/integer_range.hpp b/include/util/integer_range.hpp
index cd6052ddc..125e8d3e7 100644
--- a/include/util/integer_range.hpp
+++ b/include/util/integer_range.hpp
@@ -8,9 +8,7 @@
 
 #include <cstdint>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 // Ported from Boost.Range 1.56 due to required fix
@@ -89,7 +87,6 @@ irange(const Integer first,
 {
     return range<Integer>(first, last);
 }
-} // namespace util
 } // namespace osrm
 
 #endif // INTEGER_RANGE_HPP
diff --git a/include/util/isatty.hpp b/include/util/isatty.hpp
index fc8d8005d..151482a0b 100644
--- a/include/util/isatty.hpp
+++ b/include/util/isatty.hpp
@@ -16,9 +16,7 @@
 
 #include <cstdio>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 // Returns true if stdout is a tty, false otherwise
@@ -26,7 +24,6 @@ namespace util
 //   output is redirected to a logfile
 inline bool IsStdoutATTY() { return isatty(fileno(stdout)); }
 
-} // namespace util
 } // namespace osrm
 
 #endif
diff --git a/include/util/json_container.hpp b/include/util/json_container.hpp
index 9aaa8dfd8..3241f9078 100644
--- a/include/util/json_container.hpp
+++ b/include/util/json_container.hpp
@@ -38,30 +38,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <utility>
 #include <vector>
 
-namespace osrm
-{
-
-namespace util
-{
-
-/**
- * JSON types representing OSRM responses.
- *
- * The json::Value type represents the basic sum-type, implemented as a variant.
- *
- * There are two ways for destructuring such types:
- *  - Either provide a visitor and use the apply_visitor function or
- *  - use the get function and explicitely specify the type
- *
- * See the following documentations on variants:
- *  - https://github.com/mapbox/variant
- *  - http://www.boost.org/doc/libs/1_55_0/doc/html/variant.html
- *
- * And take a look at the example we provide.
- *
- * \see OSRM
- */
-namespace json
+namespace osrm::util::json
 {
 
 // fwd. decls.
@@ -147,8 +124,6 @@ struct Array
     std::vector<Value> values;
 };
 
-} // namespace json
-} // namespace util
 } // namespace osrm
 
 #endif // JSON_CONTAINER_HPP
diff --git a/include/util/json_deep_compare.hpp b/include/util/json_deep_compare.hpp
index 53df4fdb3..b78add60a 100644
--- a/include/util/json_deep_compare.hpp
+++ b/include/util/json_deep_compare.hpp
@@ -10,11 +10,7 @@
 #include <functional>
 #include <set>
 
-namespace osrm
-{
-namespace util
-{
-namespace json
+namespace osrm::util::json
 {
 
 struct Comparator
@@ -158,8 +154,6 @@ inline bool compare(const Value &reference, const Value &result, std::string &re
     return mapbox::util::apply_visitor(
         Comparator(reason, "reference", "result"), reference, result);
 }
-} // namespace json
-} // namespace util
 } // namespace osrm
 
 #endif
diff --git a/include/util/json_renderer.hpp b/include/util/json_renderer.hpp
index 4ca9aa3bc..2b2b50f58 100644
--- a/include/util/json_renderer.hpp
+++ b/include/util/json_renderer.hpp
@@ -16,11 +16,7 @@
 
 #include <fmt/compile.h>
 
-namespace osrm
-{
-namespace util
-{
-namespace json
+namespace osrm::util::json
 {
 
 template <typename Out> struct Renderer
@@ -165,8 +161,6 @@ inline void render(std::vector<char> &out, const Object &object)
     renderer(object);
 }
 
-} // namespace json
-} // namespace util
 } // namespace osrm
 
 #endif // JSON_RENDERER_HPP
diff --git a/include/util/json_util.hpp b/include/util/json_util.hpp
index 311263d4e..d4071c0e1 100644
--- a/include/util/json_util.hpp
+++ b/include/util/json_util.hpp
@@ -6,11 +6,7 @@
 #include <cmath>
 #include <limits>
 
-namespace osrm
-{
-namespace util
-{
-namespace json
+namespace osrm::util::json
 {
 // Make sure we don't have inf and NaN values
 template <typename T> T clamp_float(T d)
@@ -26,8 +22,6 @@ template <typename T> T clamp_float(T d)
 
     return d;
 }
-} // namespace json
-} // namespace util
 } // namespace osrm
 
 #endif // JSON_UTIL_HPP
diff --git a/include/util/log.hpp b/include/util/log.hpp
index ad963a454..1085da3ed 100644
--- a/include/util/log.hpp
+++ b/include/util/log.hpp
@@ -14,9 +14,7 @@ enum LogLevel
     logDEBUG
 };
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 class LogPolicy
@@ -104,7 +102,6 @@ class UnbufferedLog : public Log
   public:
     UnbufferedLog(LogLevel level_ = logINFO);
 };
-} // namespace util
 } // namespace osrm
 
 #endif /* LOG_HPP */
diff --git a/include/util/lua_util.hpp b/include/util/lua_util.hpp
index 0504834fd..1980aff59 100644
--- a/include/util/lua_util.hpp
+++ b/include/util/lua_util.hpp
@@ -13,9 +13,7 @@ extern "C"
 #include <iostream>
 #include <string>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 // Add the folder contain the script to the lua load path, so script can easily require() other lua
@@ -28,7 +26,6 @@ inline void luaAddScriptFolderToLoadPath(lua_State *lua_state, const char *file_
     const std::string lua_code = "package.path = \"" + folder + "/?.lua;\" .. package.path";
     luaL_dostring(lua_state, lua_code.c_str());
 }
-} // namespace util
 } // namespace osrm
 
 #endif // LUA_UTIL_HPP
diff --git a/include/util/matrix_graph_wrapper.hpp b/include/util/matrix_graph_wrapper.hpp
index 189ddfeea..44261a1e3 100644
--- a/include/util/matrix_graph_wrapper.hpp
+++ b/include/util/matrix_graph_wrapper.hpp
@@ -7,9 +7,7 @@
 
 #include "util/typedefs.hpp"
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 // This Wrapper provides all methods that are needed for extractor::TarjanSCC, when the graph is
@@ -46,7 +44,6 @@ template <typename T> class MatrixGraphWrapper
     const std::vector<T> table_;
     const std::size_t number_of_nodes_;
 };
-} // namespace util
 } // namespace osrm
 
 #endif // MATRIX_GRAPH_WRAPPER_H
diff --git a/include/util/meminfo.hpp b/include/util/meminfo.hpp
index 3409a4380..9f6d30a67 100644
--- a/include/util/meminfo.hpp
+++ b/include/util/meminfo.hpp
@@ -7,9 +7,7 @@
 #include <sys/resource.h>
 #endif
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 inline void DumpMemoryStats()
@@ -28,7 +26,6 @@ inline void DumpMemoryStats()
     util::Log() << "RAM: peak bytes used: <not implemented on Windows>";
 #endif // _WIN32
 }
-} // namespace util
 } // namespace osrm
 
 #endif
diff --git a/include/util/mmap_file.hpp b/include/util/mmap_file.hpp
index 01e829b71..11ea3d378 100644
--- a/include/util/mmap_file.hpp
+++ b/include/util/mmap_file.hpp
@@ -8,9 +8,7 @@
 #include <boost/filesystem/path.hpp>
 #include <boost/iostreams/device/mapped_file.hpp>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 namespace detail
@@ -83,7 +81,6 @@ util::vector_view<T> mmapFile(const boost::filesystem::path &file,
 {
     return detail::mmapFile<T>(file, mmap_container, size);
 }
-} // namespace util
 } // namespace osrm
 
 #endif
diff --git a/include/util/mmap_tar.hpp b/include/util/mmap_tar.hpp
index 26f223159..49a76762c 100644
--- a/include/util/mmap_tar.hpp
+++ b/include/util/mmap_tar.hpp
@@ -10,9 +10,7 @@
 #include <tuple>
 #include <unordered_map>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 using DataRange = std::pair<const char *, const char *>;
 using DataMap = std::unordered_map<std::string, DataRange>;
@@ -38,7 +36,6 @@ inline DataMap mmapTarFile(const boost::filesystem::path &path,
 
     return map;
 }
-} // namespace util
 } // namespace osrm
 
 #endif
diff --git a/include/util/msb.hpp b/include/util/msb.hpp
index 96e88d987..27d194724 100644
--- a/include/util/msb.hpp
+++ b/include/util/msb.hpp
@@ -7,9 +7,7 @@
 #include <cstdint>
 #include <utility>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 // get the msb of an integer
@@ -47,7 +45,6 @@ inline std::size_t msb(unsigned int v)
     return MSB_INDEX - __builtin_clz(v);
 }
 #endif
-} // namespace util
 } // namespace osrm
 
 #endif
diff --git a/include/util/node_based_graph.hpp b/include/util/node_based_graph.hpp
index f7fdbc41f..4a66c501d 100644
--- a/include/util/node_based_graph.hpp
+++ b/include/util/node_based_graph.hpp
@@ -13,9 +13,7 @@
 #include <memory>
 #include <utility>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 struct NodeBasedEdgeData
@@ -97,7 +95,6 @@ NodeBasedDynamicGraphFromEdges(NodeID number_of_nodes,
 
     return NodeBasedDynamicGraph(number_of_nodes, edges_list);
 }
-} // namespace util
 } // namespace osrm
 
 #endif // NODE_BASED_GRAPH_HPP
diff --git a/include/util/opening_hours.hpp b/include/util/opening_hours.hpp
index e506bd0fa..a3b7a0465 100644
--- a/include/util/opening_hours.hpp
+++ b/include/util/opening_hours.hpp
@@ -6,9 +6,7 @@
 #include <string>
 #include <vector>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 // Helper classes for "opening hours" format http://wiki.openstreetmap.org/wiki/Key:opening_hours
@@ -223,7 +221,6 @@ std::vector<OpeningHours> ParseOpeningHours(const std::string &str);
 
 bool CheckOpeningHours(const std::vector<OpeningHours> &input, const struct tm &time);
 
-} // namespace util
 } // namespace osrm
 
 #endif // OSRM_OPENING_HOURS_HPP
diff --git a/include/util/packed_vector.hpp b/include/util/packed_vector.hpp
index 306fc82ca..4e186482e 100644
--- a/include/util/packed_vector.hpp
+++ b/include/util/packed_vector.hpp
@@ -20,9 +20,7 @@
 #include <windows.h>
 #endif
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 namespace detail
 {
@@ -601,7 +599,6 @@ template <typename T, std::size_t Bits>
 using PackedVector = detail::PackedVector<T, Bits, storage::Ownership::Container>;
 template <typename T, std::size_t Bits>
 using PackedVectorView = detail::PackedVector<T, Bits, storage::Ownership::View>;
-} // namespace util
 } // namespace osrm
 
 #endif /* PACKED_VECTOR_HPP */
diff --git a/include/util/percent.hpp b/include/util/percent.hpp
index f812558e7..13f9f3549 100644
--- a/include/util/percent.hpp
+++ b/include/util/percent.hpp
@@ -7,9 +7,7 @@
 #include "util/isatty.hpp"
 #include "util/log.hpp"
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 class Percent
@@ -87,7 +85,6 @@ class Percent
         }
     }
 };
-} // namespace util
 } // namespace osrm
 
 #endif // PERCENT_HPP
diff --git a/include/util/permutation.hpp b/include/util/permutation.hpp
index 664889cc0..4bc6134bf 100644
--- a/include/util/permutation.hpp
+++ b/include/util/permutation.hpp
@@ -5,9 +5,7 @@
 
 #include <vector>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 namespace permutation_detail
@@ -67,7 +65,6 @@ std::vector<IndexT> orderingToPermutation(const std::vector<IndexT> &ordering)
 
     return permutation;
 }
-} // namespace util
 } // namespace osrm
 
 #endif
diff --git a/include/util/query_heap.hpp b/include/util/query_heap.hpp
index bf5831bfb..8027bb150 100644
--- a/include/util/query_heap.hpp
+++ b/include/util/query_heap.hpp
@@ -11,9 +11,7 @@
 #include <unordered_map>
 #include <vector>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 template <typename NodeID, typename Key> class GenerationArrayStorage
@@ -372,7 +370,6 @@ class QueryHeap
     HeapContainer heap;
     IndexStorage node_index;
 };
-} // namespace util
 } // namespace osrm
 
 #endif // OSRM_UTIL_QUERY_HEAP_HPP
diff --git a/include/util/range_table.hpp b/include/util/range_table.hpp
index aa1b89f1c..3411875c1 100644
--- a/include/util/range_table.hpp
+++ b/include/util/range_table.hpp
@@ -10,9 +10,7 @@
 #include <fstream>
 #include <utility>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 /*
  * These pre-declarations are needed because parsing C++ is hard
@@ -215,7 +213,6 @@ unsigned RangeTable<BLOCK_SIZE, Ownership>::PrefixSumAtIndex(int index, const Bl
 
     return sum;
 }
-} // namespace util
 } // namespace osrm
 
 #endif // RANGE_TABLE_HPP
diff --git a/include/util/rectangle.hpp b/include/util/rectangle.hpp
index eb53396d1..59d03ed3f 100644
--- a/include/util/rectangle.hpp
+++ b/include/util/rectangle.hpp
@@ -11,9 +11,7 @@
 
 #include <cstdint>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 struct RectangleInt2D
@@ -171,7 +169,6 @@ struct RectangleInt2D
                max_lat != FixedLatitude{std::numeric_limits<std::int32_t>::min()};
     }
 };
-} // namespace util
 } // namespace osrm
 
 #endif
diff --git a/include/util/serialization.hpp b/include/util/serialization.hpp
index c4205e67d..290023063 100644
--- a/include/util/serialization.hpp
+++ b/include/util/serialization.hpp
@@ -11,11 +11,7 @@
 #include "storage/io.hpp"
 #include "storage/serialization.hpp"
 
-namespace osrm
-{
-namespace util
-{
-namespace serialization
+namespace osrm::util::serialization
 {
 
 template <unsigned BlockSize, storage::Ownership Ownership>
@@ -143,8 +139,6 @@ void write(storage::tar::FileWriter &writer,
     storage::serialization::write(
         writer, name + "/search_tree_level_starts", rtree.m_tree_level_starts);
 }
-} // namespace serialization
-} // namespace util
 } // namespace osrm
 
 #endif
diff --git a/include/util/static_assert.hpp b/include/util/static_assert.hpp
index 985324c96..e2e036cf9 100644
--- a/include/util/static_assert.hpp
+++ b/include/util/static_assert.hpp
@@ -3,24 +3,21 @@
 
 #include <type_traits>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 template <typename It, typename Value> inline void static_assert_iter_value()
 {
-    using IterValueType = typename std::iterator_traits<It>::value_type;
+    using IterValueType = typename std::iterator_traits;<It>::value_type;
     static_assert(std::is_same<IterValueType, Value>::value, "");
 }
 
 template <typename It, typename Category> inline void static_assert_iter_category()
 {
-    using IterCategoryType = typename std::iterator_traits<It>::iterator_category;
+    using IterCategoryType = typename std::iterator_traits;<It>::iterator_category;
     static_assert(std::is_base_of<Category, IterCategoryType>::value, "");
 }
 
-} // namespace util
 } // namespace osrm
 
 #endif // OSRM_STATIC_ASSERT_HPP
diff --git a/include/util/static_graph.hpp b/include/util/static_graph.hpp
index 22cf48755..67004beb9 100644
--- a/include/util/static_graph.hpp
+++ b/include/util/static_graph.hpp
@@ -19,9 +19,7 @@
 #include <utility>
 #include <vector>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 template <typename EdgeDataT, storage::Ownership Ownership> class StaticGraph;
 
@@ -320,7 +318,6 @@ class StaticGraph
     Vector<EdgeArrayEntry> edge_array;
 };
 
-} // namespace util
 } // namespace osrm
 
 #endif // STATIC_GRAPH_HPP
diff --git a/include/util/static_rtree.hpp b/include/util/static_rtree.hpp
index 1e8cfe2bc..7d94f32ed 100644
--- a/include/util/static_rtree.hpp
+++ b/include/util/static_rtree.hpp
@@ -36,9 +36,7 @@
 #include <string>
 #include <vector>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 template <class EdgeDataT,
           storage::Ownership Ownership = storage::Ownership::Container,
@@ -774,7 +772,6 @@ class StaticRTree
 //[2] "Nearest Neighbor Queries", N. Roussopulos et al; 1995; DOI: 10.1145/223784.223794
 //[3] "Distance Browsing in Spatial Databases"; G. Hjaltason, H. Samet; 1999; ACM Trans. DB Sys
 // Vol.24 No.2, pp.265-318
-} // namespace util
 } // namespace osrm
 
 #endif // STATIC_RTREE_HPP
diff --git a/include/util/string_util.hpp b/include/util/string_util.hpp
index 3e62dc62e..a6bac54be 100644
--- a/include/util/string_util.hpp
+++ b/include/util/string_util.hpp
@@ -7,9 +7,7 @@
 #include <string>
 #include <vector>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 // precision:  position after decimal point
@@ -143,7 +141,6 @@ inline std::size_t URIDecode(const std::string &input, std::string &output)
 }
 
 inline std::size_t URIDecodeInPlace(std::string &URI) { return URIDecode(URI, URI); }
-} // namespace util
 } // namespace osrm
 
 #endif // STRING_UTIL_HPP
diff --git a/include/util/timed_histogram.hpp b/include/util/timed_histogram.hpp
index 955fe013e..176e4ba09 100644
--- a/include/util/timed_histogram.hpp
+++ b/include/util/timed_histogram.hpp
@@ -9,9 +9,7 @@
 #include <sstream>
 #include <vector>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 namespace detail
 {
@@ -88,7 +86,6 @@ template <std::size_t TimeBinSize = 1000, std::size_t IndexBinSize = 1000> class
     std::vector<std::uint32_t> frame_offsets;
     std::vector<std::uint32_t> frame_counters;
 };
-} // namespace util
 } // namespace osrm
 
 #endif
diff --git a/include/util/timezones.hpp b/include/util/timezones.hpp
index fd7c85369..6c3a64e43 100644
--- a/include/util/timezones.hpp
+++ b/include/util/timezones.hpp
@@ -12,9 +12,7 @@
 
 #include <chrono>
 
-namespace osrm
-{
-namespace updater
+namespace osrm::updater
 {
 
 // Time zone shape polygons loaded in R-tree
@@ -44,7 +42,6 @@ class Timezoner
     rtree_t rtree;
     std::vector<local_time_t> local_times;
 };
-} // namespace updater
 } // namespace osrm
 
 #endif
diff --git a/include/util/timing_util.hpp b/include/util/timing_util.hpp
index 29e9ba8d5..405c7358a 100644
--- a/include/util/timing_util.hpp
+++ b/include/util/timing_util.hpp
@@ -4,9 +4,7 @@
 #include <chrono>
 #include <cstdint>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 #define TIMER_START(_X) auto _X##_start = std::chrono::steady_clock::now(), _X##_stop = _X##_start
@@ -23,7 +21,6 @@ namespace util
      std::chrono::duration_cast<std::chrono::microseconds>(_X##_stop - _X##_start).count())
 #define TIMER_MIN(_X)                                                                              \
     std::chrono::duration_cast<std::chrono::minutes>(_X##_stop - _X##_start).count()
-} // namespace util
 } // namespace osrm
 
 #endif // TIMING_UTIL_HPP
diff --git a/include/util/to_osm_link.hpp b/include/util/to_osm_link.hpp
index 0b583041e..7768372b1 100644
--- a/include/util/to_osm_link.hpp
+++ b/include/util/to_osm_link.hpp
@@ -6,9 +6,7 @@
 #include <iomanip>
 #include <string>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 inline std::string toOSMLink(const util::FloatCoordinate &c)
 {
@@ -25,7 +23,6 @@ inline std::string toOSMLink(const util::Coordinate &c)
          << toFloating(c.lat) << "&mlon=" << toFloating(c.lon);
     return link.str();
 }
-} // namespace util
 } // namespace osrm
 
 #endif
diff --git a/include/util/trigonometry_table.hpp b/include/util/trigonometry_table.hpp
index c268d676f..ff34b2200 100644
--- a/include/util/trigonometry_table.hpp
+++ b/include/util/trigonometry_table.hpp
@@ -8,9 +8,7 @@
 
 #include <boost/math/constants/constants.hpp>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 constexpr unsigned short atan_table[4096] = {
@@ -431,7 +429,6 @@ inline double atan2_lookup(double y, double x)
     }
     return angle;
 }
-} // namespace util
 } // namespace osrm
 
 #endif // TRIGONOMETRY_TABLE_HPP
diff --git a/include/util/vector_tile.hpp b/include/util/vector_tile.hpp
index 9d4ae6e36..d2047cd62 100644
--- a/include/util/vector_tile.hpp
+++ b/include/util/vector_tile.hpp
@@ -3,16 +3,10 @@
 
 #include <cstdint>
 
-namespace osrm
-{
-namespace util
-{
-namespace vector_tile
+namespace osrm::util::vector_tile
 {
 // Vector tiles are 4096 virtual pixels on each side
 const constexpr double EXTENT = 4096.0;
 const constexpr double BUFFER = 128.0;
-} // namespace vector_tile
-} // namespace util
 } // namespace osrm
 #endif
diff --git a/include/util/vector_view.hpp b/include/util/vector_view.hpp
index 961b13c7e..323b110eb 100644
--- a/include/util/vector_view.hpp
+++ b/include/util/vector_view.hpp
@@ -19,9 +19,7 @@
 #include <utility>
 #include <vector>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 template <typename DataT>
@@ -267,7 +265,6 @@ struct is_view_or_vector
                                  std::is_same<util::vector_view<ValueT>, VectorT>::value>
 {
 };
-} // namespace util
 } // namespace osrm
 
 #endif // SHARED_MEMORY_VECTOR_WRAPPER_HPP
diff --git a/include/util/viewport.hpp b/include/util/viewport.hpp
index acd0d03c9..7188e8a55 100644
--- a/include/util/viewport.hpp
+++ b/include/util/viewport.hpp
@@ -11,11 +11,7 @@
 
 // Port of https://github.com/mapbox/geo-viewport
 
-namespace osrm
-{
-namespace util
-{
-namespace viewport
+namespace osrm::util::viewport
 {
 
 namespace detail
@@ -44,8 +40,6 @@ inline unsigned getFittedZoom(util::Coordinate south_west, util::Coordinate nort
     else
         return detail::MIN_ZOOM;
 }
-} // namespace viewport
-} // namespace util
 } // namespace osrm
 
 #endif
diff --git a/include/util/web_mercator.hpp b/include/util/web_mercator.hpp
index bb959a70d..2a0f3c1d6 100644
--- a/include/util/web_mercator.hpp
+++ b/include/util/web_mercator.hpp
@@ -5,11 +5,7 @@
 
 #include <boost/math/constants/constants.hpp>
 
-namespace osrm
-{
-namespace util
-{
-namespace web_mercator
+namespace osrm::util::web_mercator
 {
 namespace detail
 {
@@ -169,8 +165,6 @@ inline void xyzToMercator(
     maxx = static_cast<double>(clamp(util::FloatLongitude{maxx})) * DEGREE_TO_PX;
     maxy = latToY(util::FloatLatitude{maxy}) * DEGREE_TO_PX;
 }
-} // namespace web_mercator
-} // namespace util
 } // namespace osrm
 
 #endif
diff --git a/include/util/xor_fast_hash.hpp b/include/util/xor_fast_hash.hpp
index 97a83fcd4..089205459 100644
--- a/include/util/xor_fast_hash.hpp
+++ b/include/util/xor_fast_hash.hpp
@@ -12,9 +12,7 @@
 
 #include <cstdint>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 /*
@@ -65,7 +63,6 @@ template <std::size_t MaxNumElements = (1u << 16u)> class XORFastHash
         return table1[lsb] ^ table2[msb];
     }
 };
-} // namespace util
 } // namespace osrm
 
 #endif // XOR_FAST_HASH_HPP
diff --git a/include/util/xor_fast_hash_storage.hpp b/include/util/xor_fast_hash_storage.hpp
index 4746a5891..94f501aec 100644
--- a/include/util/xor_fast_hash_storage.hpp
+++ b/include/util/xor_fast_hash_storage.hpp
@@ -6,9 +6,7 @@
 #include <limits>
 #include <vector>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 template <typename NodeID, typename Key, std::size_t MaxNumElements = (1u << 16u)>
@@ -78,7 +76,6 @@ class XORFastHashStorage
     XORFastHash<MaxNumElements> fast_hasher;
     unsigned current_timestamp;
 };
-} // namespace util
 } // namespace osrm
 
 #endif // XOR_FAST_HASH_STORAGE_HPP
diff --git a/src/benchmarks/static_rtree.cpp b/src/benchmarks/static_rtree.cpp
index d40d6390e..48eb5e5e0 100644
--- a/src/benchmarks/static_rtree.cpp
+++ b/src/benchmarks/static_rtree.cpp
@@ -16,9 +16,7 @@
 
 #include <boost/filesystem/fstream.hpp>
 
-namespace osrm
-{
-namespace benchmarks
+namespace osrm::benchmarks
 {
 
 using namespace osrm::test;
@@ -74,7 +72,6 @@ void benchmark(BenchStaticRTree &rtree, unsigned num_queries)
         return rtree.Nearest(q, 10);
     });
 }
-} // namespace benchmarks
 } // namespace osrm
 
 int main(int argc, char **argv)
diff --git a/src/contractor/contractor.cpp b/src/contractor/contractor.cpp
index 5f9d7cbd2..2db7c9470 100644
--- a/src/contractor/contractor.cpp
+++ b/src/contractor/contractor.cpp
@@ -37,9 +37,7 @@
 #include <boost/assert.hpp>
 #include <tbb/global_control.h>
 
-namespace osrm
-{
-namespace contractor
+namespace osrm::contractor
 {
 
 int Contractor::Run()
@@ -125,5 +123,4 @@ int Contractor::Run()
     return 0;
 }
 
-} // namespace contractor
 } // namespace osrm
diff --git a/src/contractor/contractor_search.cpp b/src/contractor/contractor_search.cpp
index f9e336c8e..29fdf0eff 100644
--- a/src/contractor/contractor_search.cpp
+++ b/src/contractor/contractor_search.cpp
@@ -3,9 +3,7 @@
 #include "contractor/contractor_graph.hpp"
 #include "contractor/contractor_heap.hpp"
 
-namespace osrm
-{
-namespace contractor
+namespace osrm::contractor
 {
 
 namespace
@@ -85,5 +83,4 @@ void search(ContractorHeap &heap,
         relaxNode(heap, graph, node, node_weight, forbidden_node);
     }
 }
-} // namespace contractor
 } // namespace osrm
diff --git a/src/contractor/graph_contractor.cpp b/src/contractor/graph_contractor.cpp
index 07628523d..063fe2872 100644
--- a/src/contractor/graph_contractor.cpp
+++ b/src/contractor/graph_contractor.cpp
@@ -23,9 +23,7 @@
 #include <memory>
 #include <vector>
 
-namespace osrm
-{
-namespace contractor
+namespace osrm::contractor
 {
 namespace
 {
@@ -768,5 +766,4 @@ std::vector<bool> contractGraph(ContractorGraph &graph,
     return std::move(node_data.is_core);
 }
 
-} // namespace contractor
 } // namespace osrm
diff --git a/src/customize/customizer.cpp b/src/customize/customizer.cpp
index 00eb6f827..53d2fd627 100644
--- a/src/customize/customizer.cpp
+++ b/src/customize/customizer.cpp
@@ -23,9 +23,7 @@
 
 #include <tbb/global_control.h>
 
-namespace osrm
-{
-namespace customizer
+namespace osrm::customizer
 {
 
 namespace
@@ -183,5 +181,4 @@ int Customizer::Run(const CustomizationConfig &config)
     return 0;
 }
 
-} // namespace customizer
 } // namespace osrm
diff --git a/src/engine/api/json_factory.cpp b/src/engine/api/json_factory.cpp
index c2bcbb841..7c3010d81 100644
--- a/src/engine/api/json_factory.cpp
+++ b/src/engine/api/json_factory.cpp
@@ -21,13 +21,7 @@
 
 using TurnInstruction = osrm::guidance::TurnInstruction;
 
-namespace osrm
-{
-namespace engine
-{
-namespace api
-{
-namespace json
+namespace osrm::engine::api::json
 {
 namespace detail
 {
@@ -294,7 +288,4 @@ util::json::Array makeRouteLegs(std::vector<guidance::RouteLeg> legs,
     }
     return json_legs;
 }
-} // namespace json
-} // namespace api
-} // namespace engine
 } // namespace osrm
diff --git a/src/engine/datafacade/mmap_memory_allocator.cpp b/src/engine/datafacade/mmap_memory_allocator.cpp
index 765b05d31..aa0e2c6cb 100644
--- a/src/engine/datafacade/mmap_memory_allocator.cpp
+++ b/src/engine/datafacade/mmap_memory_allocator.cpp
@@ -10,11 +10,7 @@
 
 #include <boost/assert.hpp>
 
-namespace osrm
-{
-namespace engine
-{
-namespace datafacade
+namespace osrm::engine::datafacade
 {
 
 MMapMemoryAllocator::MMapMemoryAllocator(const storage::StorageConfig &config)
@@ -67,6 +63,4 @@ MMapMemoryAllocator::~MMapMemoryAllocator() {}
 
 const storage::SharedDataIndex &MMapMemoryAllocator::GetIndex() { return index; }
 
-} // namespace datafacade
-} // namespace engine
 } // namespace osrm
diff --git a/src/engine/datafacade/process_memory_allocator.cpp b/src/engine/datafacade/process_memory_allocator.cpp
index ed07d669f..0957bdf2b 100644
--- a/src/engine/datafacade/process_memory_allocator.cpp
+++ b/src/engine/datafacade/process_memory_allocator.cpp
@@ -3,11 +3,7 @@
 
 #include "boost/assert.hpp"
 
-namespace osrm
-{
-namespace engine
-{
-namespace datafacade
+namespace osrm::engine::datafacade
 {
 
 ProcessMemoryAllocator::ProcessMemoryAllocator(const storage::StorageConfig &config)
@@ -38,6 +34,4 @@ ProcessMemoryAllocator::~ProcessMemoryAllocator() {}
 
 const storage::SharedDataIndex &ProcessMemoryAllocator::GetIndex() { return index; }
 
-} // namespace datafacade
-} // namespace engine
 } // namespace osrm
diff --git a/src/engine/datafacade/shared_memory_allocator.cpp b/src/engine/datafacade/shared_memory_allocator.cpp
index d90302bf9..3a99eef12 100644
--- a/src/engine/datafacade/shared_memory_allocator.cpp
+++ b/src/engine/datafacade/shared_memory_allocator.cpp
@@ -6,11 +6,7 @@
 
 #include "boost/assert.hpp"
 
-namespace osrm
-{
-namespace engine
-{
-namespace datafacade
+namespace osrm::engine::datafacade
 {
 
 SharedMemoryAllocator::SharedMemoryAllocator(
@@ -41,6 +37,4 @@ SharedMemoryAllocator::~SharedMemoryAllocator() {}
 
 const storage::SharedDataIndex &SharedMemoryAllocator::GetIndex() { return index; }
 
-} // namespace datafacade
-} // namespace engine
 } // namespace osrm
diff --git a/src/engine/douglas_peucker.cpp b/src/engine/douglas_peucker.cpp
index 424f94940..c40f37fe9 100644
--- a/src/engine/douglas_peucker.cpp
+++ b/src/engine/douglas_peucker.cpp
@@ -12,9 +12,7 @@
 #include <stack>
 #include <utility>
 
-namespace osrm
-{
-namespace engine
+namespace osrm::engine
 {
 
 // Normed to the thresholds table
@@ -119,5 +117,4 @@ std::vector<util::Coordinate> douglasPeucker(std::vector<util::Coordinate>::cons
 
     return simplified_geometry;
 }
-} // namespace engine
 } // namespace osrm
diff --git a/src/engine/engine_config.cpp b/src/engine/engine_config.cpp
index c227a9b8a..117fe2d25 100644
--- a/src/engine/engine_config.cpp
+++ b/src/engine/engine_config.cpp
@@ -1,8 +1,6 @@
 #include "engine/engine_config.hpp"
 
-namespace osrm
-{
-namespace engine
+namespace osrm::engine
 {
 
 bool EngineConfig::IsValid() const
@@ -27,5 +25,4 @@ bool EngineConfig::IsValid() const
             storage_config.IsValid()) &&
            limits_valid;
 }
-} // namespace engine
 } // namespace osrm
diff --git a/src/engine/guidance/assemble_overview.cpp b/src/engine/guidance/assemble_overview.cpp
index 75def77a0..475a9c452 100644
--- a/src/engine/guidance/assemble_overview.cpp
+++ b/src/engine/guidance/assemble_overview.cpp
@@ -9,11 +9,7 @@
 #include <utility>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace guidance
+namespace osrm::engine::guidance
 {
 namespace
 {
@@ -90,6 +86,4 @@ std::vector<util::Coordinate> assembleOverview(const std::vector<LegGeometry> &l
     return overview_geometry;
 }
 
-} // namespace guidance
-} // namespace engine
 } // namespace osrm
diff --git a/src/engine/guidance/assemble_route.cpp b/src/engine/guidance/assemble_route.cpp
index a2b4fc444..8db84504e 100644
--- a/src/engine/guidance/assemble_route.cpp
+++ b/src/engine/guidance/assemble_route.cpp
@@ -2,11 +2,7 @@
 
 #include <numeric>
 
-namespace osrm
-{
-namespace engine
-{
-namespace guidance
+namespace osrm::engine::guidance
 {
 
 Route assembleRoute(const std::vector<RouteLeg> &route_legs)
@@ -27,6 +23,4 @@ Route assembleRoute(const std::vector<RouteLeg> &route_legs)
     return Route{distance, duration, weight};
 }
 
-} // namespace guidance
-} // namespace engine
 } // namespace osrm
diff --git a/src/engine/guidance/assemble_steps.cpp b/src/engine/guidance/assemble_steps.cpp
index 1e5b87a3f..e9d37259b 100644
--- a/src/engine/guidance/assemble_steps.cpp
+++ b/src/engine/guidance/assemble_steps.cpp
@@ -8,13 +8,7 @@
 #include <cmath>
 #include <cstddef>
 
-namespace osrm
-{
-namespace engine
-{
-namespace guidance
-{
-namespace detail
+namespace osrm::engine::guidance::detail
 {
 
 std::pair<short, short> getDepartBearings(const LegGeometry &leg_geometry,
@@ -50,7 +44,4 @@ std::pair<short, short> getArriveBearings(const LegGeometry &leg_geometry,
     return std::make_pair<short, short>(
         std::round(util::coordinate_calculation::bearing(pre_turn_coordinate, turn_coordinate)), 0);
 }
-} // namespace detail
-} // namespace guidance
-} // namespace engine
 } // namespace osrm
diff --git a/src/engine/guidance/collapse_scenario_detection.cpp b/src/engine/guidance/collapse_scenario_detection.cpp
index ff29bb756..e23c89f01 100644
--- a/src/engine/guidance/collapse_scenario_detection.cpp
+++ b/src/engine/guidance/collapse_scenario_detection.cpp
@@ -6,11 +6,7 @@
 
 #include <boost/assert.hpp>
 
-namespace osrm
-{
-namespace engine
-{
-namespace guidance
+namespace osrm::engine::guidance
 {
 using namespace osrm::guidance;
 
@@ -419,6 +415,4 @@ bool straightTurnFollowedByChoiceless(const RouteStepIterator step_entering_inte
            noIntermediaryIntersections(*step_entering_intersection);
 }
 
-} /* namespace guidance */
-} /* namespace engine */
 } /* namespace osrm */
diff --git a/src/engine/guidance/collapse_turns.cpp b/src/engine/guidance/collapse_turns.cpp
index d6a40cec0..160797496 100644
--- a/src/engine/guidance/collapse_turns.cpp
+++ b/src/engine/guidance/collapse_turns.cpp
@@ -10,11 +10,7 @@
 
 #include <boost/assert.hpp>
 
-namespace osrm
-{
-namespace engine
-{
-namespace guidance
+namespace osrm::engine::guidance
 {
 using osrm::util::angularDeviation;
 using namespace osrm::guidance;
@@ -667,6 +663,4 @@ RouteSteps collapseSegregatedTurnInstructions(RouteSteps steps)
     return steps;
 }
 
-} // namespace guidance
-} // namespace engine
 } // namespace osrm
diff --git a/src/engine/guidance/lane_processing.cpp b/src/engine/guidance/lane_processing.cpp
index 4a69f102c..3e253c450 100644
--- a/src/engine/guidance/lane_processing.cpp
+++ b/src/engine/guidance/lane_processing.cpp
@@ -9,11 +9,7 @@
 #include <unordered_set>
 #include <utility>
 
-namespace osrm
-{
-namespace engine
-{
-namespace guidance
+namespace osrm::engine::guidance
 {
 using namespace osrm::guidance;
 
@@ -209,6 +205,4 @@ std::vector<RouteStep> anticipateLaneChange(std::vector<RouteStep> steps,
     return steps;
 }
 
-} // namespace guidance
-} // namespace engine
 } // namespace osrm
diff --git a/src/engine/guidance/post_processing.cpp b/src/engine/guidance/post_processing.cpp
index 8b18bcae2..b81936bd3 100644
--- a/src/engine/guidance/post_processing.cpp
+++ b/src/engine/guidance/post_processing.cpp
@@ -21,11 +21,7 @@
 #include <limits>
 #include <utility>
 
-namespace osrm
-{
-namespace engine
-{
-namespace guidance
+namespace osrm::engine::guidance
 {
 using namespace osrm::guidance;
 
@@ -718,6 +714,4 @@ void applyOverrides(const datafacade::BaseDataFacade &facade,
     }
 }
 
-} // namespace guidance
-} // namespace engine
 } // namespace osrm
diff --git a/src/engine/guidance/verbosity_reduction.cpp b/src/engine/guidance/verbosity_reduction.cpp
index 3351c853c..ad1da8f70 100644
--- a/src/engine/guidance/verbosity_reduction.cpp
+++ b/src/engine/guidance/verbosity_reduction.cpp
@@ -4,11 +4,7 @@
 #include <boost/assert.hpp>
 #include <iterator>
 
-namespace osrm
-{
-namespace engine
-{
-namespace guidance
+namespace osrm::engine::guidance
 {
 using namespace osrm::guidance;
 
@@ -85,6 +81,4 @@ std::vector<RouteStep> suppressShortNameSegments(std::vector<RouteStep> steps)
     return removeNoTurnInstructions(std::move(steps));
 }
 
-} // namespace guidance
-} // namespace engine
 } // namespace osrm
diff --git a/src/engine/hint.cpp b/src/engine/hint.cpp
index d2bfcd330..9f0cb70b1 100644
--- a/src/engine/hint.cpp
+++ b/src/engine/hint.cpp
@@ -9,9 +9,7 @@
 #include <tuple>
 #include <unordered_set>
 
-namespace osrm
-{
-namespace engine
+namespace osrm::engine
 {
 
 bool SegmentHint::IsValid(const util::Coordinate new_input_coordinates,
@@ -124,5 +122,4 @@ bool Hint::IsValid(const util::Coordinate new_input_coordinates,
     return true;
 }
 
-} // namespace engine
 } // namespace osrm
diff --git a/src/engine/plugins/match.cpp b/src/engine/plugins/match.cpp
index 0400bb6f5..79b8dcc88 100644
--- a/src/engine/plugins/match.cpp
+++ b/src/engine/plugins/match.cpp
@@ -16,11 +16,7 @@
 #include <set>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace plugins
+namespace osrm::engine::plugins
 {
 
 // Filters PhantomNodes to obtain a set of viable candidates
@@ -314,6 +310,4 @@ Status MatchPlugin::HandleRequest(const RoutingAlgorithmsInterface &algorithms,
 
     return Status::Ok;
 }
-} // namespace plugins
-} // namespace engine
 } // namespace osrm
diff --git a/src/engine/plugins/nearest.cpp b/src/engine/plugins/nearest.cpp
index 96a67b13d..6f910e153 100644
--- a/src/engine/plugins/nearest.cpp
+++ b/src/engine/plugins/nearest.cpp
@@ -7,11 +7,7 @@
 #include <boost/assert.hpp>
 #include <boost/numeric/conversion/cast.hpp>
 
-namespace osrm
-{
-namespace engine
-{
-namespace plugins
+namespace osrm::engine::plugins
 {
 
 NearestPlugin::NearestPlugin(const int max_results_) : max_results{max_results_} {}
@@ -57,6 +53,4 @@ Status NearestPlugin::HandleRequest(const RoutingAlgorithmsInterface &algorithms
 
     return Status::Ok;
 }
-} // namespace plugins
-} // namespace engine
 } // namespace osrm
diff --git a/src/engine/plugins/table.cpp b/src/engine/plugins/table.cpp
index 0d760ae92..d25bbf888 100644
--- a/src/engine/plugins/table.cpp
+++ b/src/engine/plugins/table.cpp
@@ -11,11 +11,7 @@
 
 #include <boost/assert.hpp>
 
-namespace osrm
-{
-namespace engine
-{
-namespace plugins
+namespace osrm::engine::plugins
 {
 
 TablePlugin::TablePlugin(const int max_locations_distance_table)
@@ -157,6 +153,4 @@ Status TablePlugin::HandleRequest(const RoutingAlgorithmsInterface &algorithms,
 
     return Status::Ok;
 }
-} // namespace plugins
-} // namespace engine
 } // namespace osrm
diff --git a/src/engine/plugins/tile.cpp b/src/engine/plugins/tile.cpp
index d01d00204..59b6ec7d8 100644
--- a/src/engine/plugins/tile.cpp
+++ b/src/engine/plugins/tile.cpp
@@ -26,11 +26,7 @@
 #include <cmath>
 #include <cstdint>
 
-namespace osrm
-{
-namespace engine
-{
-namespace plugins
+namespace osrm::engine::plugins
 {
 
 constexpr const static int MIN_ZOOM_FOR_TURNS = 15;
@@ -695,6 +691,4 @@ Status TilePlugin::HandleRequest(const RoutingAlgorithmsInterface &algorithms,
 
     return Status::Ok;
 }
-} // namespace plugins
-} // namespace engine
 } // namespace osrm
diff --git a/src/engine/plugins/trip.cpp b/src/engine/plugins/trip.cpp
index 771529151..793fb67ba 100644
--- a/src/engine/plugins/trip.cpp
+++ b/src/engine/plugins/trip.cpp
@@ -13,11 +13,7 @@
 #include <utility>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace plugins
+namespace osrm::engine::plugins
 {
 
 bool IsStronglyConnectedComponent(const util::DistTableWrapper<EdgeDuration> &result_table)
@@ -297,6 +293,4 @@ Status TripPlugin::HandleRequest(const RoutingAlgorithmsInterface &algorithms,
 
     return Status::Ok;
 }
-} // namespace plugins
-} // namespace engine
 } // namespace osrm
diff --git a/src/engine/plugins/viaroute.cpp b/src/engine/plugins/viaroute.cpp
index bc71adceb..5ec5edeaf 100644
--- a/src/engine/plugins/viaroute.cpp
+++ b/src/engine/plugins/viaroute.cpp
@@ -12,11 +12,7 @@
 #include <string>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace plugins
+namespace osrm::engine::plugins
 {
 
 ViaRoutePlugin::ViaRoutePlugin(int max_locations_viaroute, int max_alternatives)
@@ -186,6 +182,4 @@ Status ViaRoutePlugin::HandleRequest(const RoutingAlgorithmsInterface &algorithm
 
     return Status::Ok;
 }
-} // namespace plugins
-} // namespace engine
 } // namespace osrm
diff --git a/src/engine/polyline_compressor.cpp b/src/engine/polyline_compressor.cpp
index ca9a4f2a0..a46e19eef 100644
--- a/src/engine/polyline_compressor.cpp
+++ b/src/engine/polyline_compressor.cpp
@@ -7,11 +7,7 @@
 #include <cstddef>
 #include <cstdlib>
 
-namespace osrm
-{
-namespace engine
-{
-namespace detail // anonymous to keep TU local
+namespace osrm::engine::detail // anonymous to keep TU local
 {
 
 std::string encode(int number_to_encode)
@@ -75,6 +71,4 @@ std::int32_t decode_polyline_integer(std::string::const_iterator &first,
     result = ((result & 1) == 1) ? ~(result >> 1) : (result >> 1);
     return static_cast<std::int32_t>(result);
 }
-} // namespace detail
-} // namespace engine
 } // namespace osrm
diff --git a/src/engine/routing_algorithms/alternative_path_ch.cpp b/src/engine/routing_algorithms/alternative_path_ch.cpp
index eda03e664..2337d00fc 100644
--- a/src/engine/routing_algorithms/alternative_path_ch.cpp
+++ b/src/engine/routing_algorithms/alternative_path_ch.cpp
@@ -11,11 +11,7 @@
 #include <unordered_set>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace routing_algorithms
+namespace osrm::engine::routing_algorithms
 {
 
 // Unqualified calls below are from the ch namespace.
@@ -854,6 +850,4 @@ InternalManyRoutesResult alternativePathSearch(SearchEngineData<Algorithm> &engi
     return InternalManyRoutesResult{{std::move(primary_route), std::move(secondary_route)}};
 }
 
-} // namespace routing_algorithms
-} // namespace engine
 } // namespace osrm
diff --git a/src/engine/routing_algorithms/alternative_path_mld.cpp b/src/engine/routing_algorithms/alternative_path_mld.cpp
index bc520eb78..350238061 100644
--- a/src/engine/routing_algorithms/alternative_path_mld.cpp
+++ b/src/engine/routing_algorithms/alternative_path_mld.cpp
@@ -15,11 +15,7 @@
 
 #include <boost/iterator/function_output_iterator.hpp>
 
-namespace osrm
-{
-namespace engine
-{
-namespace routing_algorithms
+namespace osrm::engine::routing_algorithms
 {
 
 // Unqualified calls below are from the mld namespace.
@@ -960,6 +956,4 @@ InternalManyRoutesResult alternativePathSearch(SearchEngineData<Algorithm> &sear
     return InternalManyRoutesResult{std::move(routes)};
 }
 
-} // namespace routing_algorithms
-} // namespace engine
 } // namespace osrm
diff --git a/src/engine/routing_algorithms/direct_shortest_path.cpp b/src/engine/routing_algorithms/direct_shortest_path.cpp
index 267ecf2f4..3bcb2e840 100644
--- a/src/engine/routing_algorithms/direct_shortest_path.cpp
+++ b/src/engine/routing_algorithms/direct_shortest_path.cpp
@@ -3,11 +3,7 @@
 #include "engine/routing_algorithms/routing_base_ch.hpp"
 #include "engine/routing_algorithms/routing_base_mld.hpp"
 
-namespace osrm
-{
-namespace engine
-{
-namespace routing_algorithms
+namespace osrm::engine::routing_algorithms
 {
 
 /// This is a stripped down version of the general shortest path algorithm.
@@ -91,6 +87,4 @@ InternalRouteResult directShortestPathSearch(SearchEngineData<mld::Algorithm> &e
     return extractRoute(facade, weight, endpoint_candidates, unpacked_nodes, unpacked_edges);
 }
 
-} // namespace routing_algorithms
-} // namespace engine
 } // namespace osrm
diff --git a/src/engine/routing_algorithms/many_to_many_ch.cpp b/src/engine/routing_algorithms/many_to_many_ch.cpp
index 28e15dfd6..616f8da2d 100644
--- a/src/engine/routing_algorithms/many_to_many_ch.cpp
+++ b/src/engine/routing_algorithms/many_to_many_ch.cpp
@@ -8,11 +8,7 @@
 #include <memory>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace routing_algorithms
+namespace osrm::engine::routing_algorithms
 {
 
 namespace ch
@@ -251,6 +247,4 @@ manyToManySearch(SearchEngineData<ch::Algorithm> &engine_working_data,
     return std::make_pair(std::move(durations_table), std::move(distances_table));
 }
 
-} // namespace routing_algorithms
-} // namespace engine
 } // namespace osrm
diff --git a/src/engine/routing_algorithms/many_to_many_mld.cpp b/src/engine/routing_algorithms/many_to_many_mld.cpp
index b206e5de7..4ebdc97fe 100644
--- a/src/engine/routing_algorithms/many_to_many_mld.cpp
+++ b/src/engine/routing_algorithms/many_to_many_mld.cpp
@@ -9,11 +9,7 @@
 #include <unordered_map>
 #include <vector>
 
-namespace osrm
-{
-namespace engine
-{
-namespace routing_algorithms
+namespace osrm::engine::routing_algorithms
 {
 
 namespace mld
@@ -676,6 +672,4 @@ manyToManySearch(SearchEngineData<mld::Algorithm> &engine_working_data,
                                                     calculate_distance);
 }
 
-} // namespace routing_algorithms
-} // namespace engine
 } // namespace osrm
diff --git a/src/engine/routing_algorithms/map_matching.cpp b/src/engine/routing_algorithms/map_matching.cpp
index 21519900b..e9c1534a3 100644
--- a/src/engine/routing_algorithms/map_matching.cpp
+++ b/src/engine/routing_algorithms/map_matching.cpp
@@ -17,11 +17,7 @@
 #include <numeric>
 #include <utility>
 
-namespace osrm
-{
-namespace engine
-{
-namespace routing_algorithms
+namespace osrm::engine::routing_algorithms
 {
 
 namespace
@@ -457,8 +453,6 @@ mapMatching(SearchEngineData<mld::Algorithm> &engine_working_data,
             const std::vector<boost::optional<double>> &trace_gps_precision,
             const bool allow_splitting);
 
-} // namespace routing_algorithms
-} // namespace engine
 } // namespace osrm
 
 //[1] "Hidden Markov Map Matching Through Noise and Sparseness"; P. Newson and J. Krumm; 2009; ACM
diff --git a/src/engine/routing_algorithms/routing_base.cpp b/src/engine/routing_algorithms/routing_base.cpp
index ee8a99ba3..6f22b097c 100644
--- a/src/engine/routing_algorithms/routing_base.cpp
+++ b/src/engine/routing_algorithms/routing_base.cpp
@@ -1,10 +1,6 @@
 #include "engine/routing_algorithms/routing_base.hpp"
 
-namespace osrm
-{
-namespace engine
-{
-namespace routing_algorithms
+namespace osrm::engine::routing_algorithms
 {
 
 bool requiresForwardLoop(const PhantomNode &source, const PhantomNode &target)
@@ -107,6 +103,4 @@ PhantomEndpoints endpointsFromCandidates(const PhantomEndpointCandidates &candid
     return PhantomEndpoints{*source_it, *target_it};
 }
 
-} // namespace routing_algorithms
-} // namespace engine
 } // namespace osrm
diff --git a/src/engine/routing_algorithms/routing_base_ch.cpp b/src/engine/routing_algorithms/routing_base_ch.cpp
index 799661897..a97e76275 100644
--- a/src/engine/routing_algorithms/routing_base_ch.cpp
+++ b/src/engine/routing_algorithms/routing_base_ch.cpp
@@ -1,12 +1,6 @@
 #include "engine/routing_algorithms/routing_base_ch.hpp"
 
-namespace osrm
-{
-namespace engine
-{
-namespace routing_algorithms
-{
-namespace ch
+namespace osrm::engine::routing_algorithms::ch
 {
 
 /**
@@ -208,8 +202,4 @@ double getNetworkDistance(SearchEngineData<Algorithm> &engine_working_data,
 
     return getPathDistance(facade, unpacked_path, source_phantom, target_phantom);
 }
-} // namespace ch
-
-} // namespace routing_algorithms
-} // namespace engine
 } // namespace osrm
diff --git a/src/engine/routing_algorithms/shortest_path.cpp b/src/engine/routing_algorithms/shortest_path.cpp
index e850de777..e4bd78e72 100644
--- a/src/engine/routing_algorithms/shortest_path.cpp
+++ b/src/engine/routing_algorithms/shortest_path.cpp
@@ -2,11 +2,7 @@
 #include "engine/routing_algorithms/routing_base_mld.hpp"
 #include "engine/routing_algorithms/shortest_path_impl.hpp"
 
-namespace osrm
-{
-namespace engine
-{
-namespace routing_algorithms
+namespace osrm::engine::routing_algorithms
 {
 
 template InternalRouteResult
@@ -21,6 +17,4 @@ shortestPathSearch(SearchEngineData<mld::Algorithm> &engine_working_data,
                    const std::vector<PhantomNodeCandidates> &waypoint_candidates,
                    const boost::optional<bool> continue_straight_at_waypoint);
 
-} // namespace routing_algorithms
-} // namespace engine
 } // namespace osrm
diff --git a/src/engine/routing_algorithms/tile_turns.cpp b/src/engine/routing_algorithms/tile_turns.cpp
index f7a65d46b..917387bfb 100644
--- a/src/engine/routing_algorithms/tile_turns.cpp
+++ b/src/engine/routing_algorithms/tile_turns.cpp
@@ -1,10 +1,6 @@
 #include "engine/routing_algorithms/tile_turns.hpp"
 
-namespace osrm
-{
-namespace engine
-{
-namespace routing_algorithms
+namespace osrm::engine::routing_algorithms
 {
 
 namespace
@@ -269,6 +265,4 @@ std::vector<TurnData> getTileTurns(const DataFacade<mld::Algorithm> &facade,
     return generateTurns(facade, edges, sorted_edge_indexes, edge_finder);
 }
 
-} // namespace routing_algorithms
-} // namespace engine
 } // namespace osrm
diff --git a/src/engine/search_engine_data.cpp b/src/engine/search_engine_data.cpp
index fc35adbff..38d9a33f2 100644
--- a/src/engine/search_engine_data.cpp
+++ b/src/engine/search_engine_data.cpp
@@ -1,8 +1,6 @@
 #include "engine/search_engine_data.hpp"
 
-namespace osrm
-{
-namespace engine
+namespace osrm::engine
 {
 
 // CH heaps
@@ -130,5 +128,4 @@ void SearchEngineData<MLD>::InitializeOrClearManyToManyThreadLocalStorage(
         many_to_many_heap.reset(new ManyToManyQueryHeap(number_of_nodes, number_of_boundary_nodes));
     }
 }
-} // namespace engine
 } // namespace osrm
diff --git a/src/extractor/compressed_edge_container.cpp b/src/extractor/compressed_edge_container.cpp
index 0ed876f51..caf0b5867 100644
--- a/src/extractor/compressed_edge_container.cpp
+++ b/src/extractor/compressed_edge_container.cpp
@@ -11,9 +11,7 @@
 
 #include <iostream>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 CompressedEdgeContainer::CompressedEdgeContainer()
@@ -399,5 +397,4 @@ std::unique_ptr<SegmentDataContainer> CompressedEdgeContainer::ToSegmentData()
 
     return std::move(segment_data);
 }
-} // namespace extractor
 } // namespace osrm
diff --git a/src/extractor/edge_based_graph_factory.cpp b/src/extractor/edge_based_graph_factory.cpp
index 547fece7c..60c961ff6 100644
--- a/src/extractor/edge_based_graph_factory.cpp
+++ b/src/extractor/edge_based_graph_factory.cpp
@@ -34,9 +34,7 @@
 #include <tbb/parallel_for.h>
 #include <tbb/parallel_pipeline.h>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 // Configuration to find representative candidate for turn angle calculations
@@ -1291,5 +1289,4 @@ EdgeBasedGraphFactory::IndexConditionals(std::vector<Conditional> &&conditionals
     return indexed_restrictions;
 }
 
-} // namespace extractor
 } // namespace osrm
diff --git a/src/extractor/extraction_containers.cpp b/src/extractor/extraction_containers.cpp
index 7908cc798..d3e9b33c7 100644
--- a/src/extractor/extraction_containers.cpp
+++ b/src/extractor/extraction_containers.cpp
@@ -378,9 +378,7 @@ get_via_node_path_from_OSM_ids(const std::string &turn_relation_type,
 
 } // namespace
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 ExtractionContainers::ExtractionContainers()
@@ -1310,5 +1308,4 @@ void ExtractionContainers::PrepareRestrictions(const ReferencedWays &restriction
     }
 }
 
-} // namespace extractor
 } // namespace osrm
diff --git a/src/extractor/extractor.cpp b/src/extractor/extractor.cpp
index 5b444d470..48ef315b1 100644
--- a/src/extractor/extractor.cpp
+++ b/src/extractor/extractor.cpp
@@ -58,9 +58,7 @@
 #include <unordered_map>
 #include <vector>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 namespace
@@ -911,5 +909,4 @@ void Extractor::ProcessGuidanceTurns(
     util::Log() << "ok, after " << TIMER_SEC(write_guidance_data) << "s";
 }
 
-} // namespace extractor
 } // namespace osrm
diff --git a/src/extractor/extractor_callbacks.cpp b/src/extractor/extractor_callbacks.cpp
index 51051d768..b9411bbf2 100644
--- a/src/extractor/extractor_callbacks.cpp
+++ b/src/extractor/extractor_callbacks.cpp
@@ -40,9 +40,7 @@ const ByEdgeOrByMeterValue::ValueByMeter ByEdgeOrByMeterValue::by_meter;
 #endif
 #endif
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 ExtractorCallbacks::ExtractorCallbacks(ExtractionContainers &extraction_containers_,
                                        std::unordered_map<std::string, ClassData> &classes_map,
@@ -492,5 +490,4 @@ void ExtractorCallbacks::ProcessWay(const osmium::Way &input_way, const Extracti
     external_memory.way_node_id_offsets.push_back(external_memory.used_node_id_list.size());
 }
 
-} // namespace extractor
 } // namespace osrm
diff --git a/src/extractor/graph_compressor.cpp b/src/extractor/graph_compressor.cpp
index ca0bbac11..26875562e 100644
--- a/src/extractor/graph_compressor.cpp
+++ b/src/extractor/graph_compressor.cpp
@@ -14,9 +14,7 @@
 #include <boost/assert.hpp>
 #include <unordered_set>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 static constexpr int SECOND_TO_DECISECOND = 10;
@@ -419,5 +417,4 @@ void GraphCompressor::PrintStatistics(unsigned original_number_of_nodes,
     util::Log() << "Node compression ratio: " << new_node_count / (double)original_number_of_nodes;
     util::Log() << "Edge compression ratio: " << new_edge_count / (double)original_number_of_edges;
 }
-} // namespace extractor
 } // namespace osrm
diff --git a/src/extractor/intersection/coordinate_extractor.cpp b/src/extractor/intersection/coordinate_extractor.cpp
index ea99613fc..96bb1d77a 100644
--- a/src/extractor/intersection/coordinate_extractor.cpp
+++ b/src/extractor/intersection/coordinate_extractor.cpp
@@ -11,11 +11,7 @@
 #include "util/bearing.hpp"
 #include "util/coordinate_calculation.hpp"
 
-namespace osrm
-{
-namespace extractor
-{
-namespace intersection
+namespace osrm::extractor::intersection
 {
 
 namespace
@@ -1171,6 +1167,4 @@ CoordinateExtractor::RegressionLine(const std::vector<util::Coordinate> &coordin
     return {coord_between_front, coord_between_back};
 }
 
-} // namespace intersection
-} // namespace extractor
 } // namespace osrm
diff --git a/src/extractor/intersection/have_identical_names.cpp b/src/extractor/intersection/have_identical_names.cpp
index 3714598ec..4384e498c 100644
--- a/src/extractor/intersection/have_identical_names.cpp
+++ b/src/extractor/intersection/have_identical_names.cpp
@@ -2,11 +2,7 @@
 
 #include "util/guidance/name_announcements.hpp"
 
-namespace osrm
-{
-namespace extractor
-{
-namespace intersection
+namespace osrm::extractor::intersection
 {
 
 // check if two name ids can be seen as identical (in presence of refs/others)
@@ -25,6 +21,4 @@ bool HaveIdenticalNames(const NameID lhs,
            !util::guidance::requiresNameAnnounced(rhs, lhs, name_table, street_name_suffix_table);
 }
 
-} // namespace intersection
-} // namespace extractor
 } // namespace osrm
diff --git a/src/extractor/intersection/intersection.cpp b/src/extractor/intersection/intersection.cpp
index 530252a4c..44f9918a4 100644
--- a/src/extractor/intersection/intersection.cpp
+++ b/src/extractor/intersection/intersection.cpp
@@ -5,11 +5,7 @@
 
 #include <boost/range/adaptors.hpp>
 
-namespace osrm
-{
-namespace extractor
-{
-namespace intersection
+namespace osrm::extractor::intersection
 {
 
 bool IntersectionViewData::CompareByAngle(const IntersectionViewData &other) const
@@ -37,6 +33,4 @@ std::string toString(const IntersectionViewData &view)
     return result;
 }
 
-} // namespace intersection
-} // namespace extractor
 } // namespace osrm
diff --git a/src/extractor/intersection/intersection_analysis.cpp b/src/extractor/intersection/intersection_analysis.cpp
index 9a3ad1f10..9dc00e971 100644
--- a/src/extractor/intersection/intersection_analysis.cpp
+++ b/src/extractor/intersection/intersection_analysis.cpp
@@ -7,11 +7,7 @@
 
 #include <boost/optional/optional_io.hpp>
 
-namespace osrm
-{
-namespace extractor
-{
-namespace intersection
+namespace osrm::extractor::intersection
 {
 
 IntersectionEdges getIncomingEdges(const util::NodeBasedDynamicGraph &graph,
@@ -856,6 +852,4 @@ IntersectionEdge skipDegreeTwoNodes(const util::NodeBasedDynamicGraph &graph, In
 
     return road;
 }
-} // namespace intersection
-} // namespace extractor
 } // namespace osrm
diff --git a/src/extractor/intersection/mergable_road_detector.cpp b/src/extractor/intersection/mergable_road_detector.cpp
index a1c95054c..edda82cfc 100644
--- a/src/extractor/intersection/mergable_road_detector.cpp
+++ b/src/extractor/intersection/mergable_road_detector.cpp
@@ -12,11 +12,7 @@
 
 using osrm::util::angularDeviation;
 
-namespace osrm
-{
-namespace extractor
-{
-namespace intersection
+namespace osrm::extractor::intersection
 {
 
 namespace
@@ -616,6 +612,4 @@ bool MergableRoadDetector::IsLinkRoad(const NodeID intersection_node,
                        .annotation_data));
 }
 
-} // namespace intersection
-} // namespace extractor
 } // namespace osrm
diff --git a/src/extractor/intersection/node_based_graph_walker.cpp b/src/extractor/intersection/node_based_graph_walker.cpp
index 308a467b2..2a8defe8e 100644
--- a/src/extractor/intersection/node_based_graph_walker.cpp
+++ b/src/extractor/intersection/node_based_graph_walker.cpp
@@ -7,11 +7,7 @@
 
 using osrm::util::angularDeviation;
 
-namespace osrm
-{
-namespace extractor
-{
-namespace intersection
+namespace osrm::extractor::intersection
 {
 
 // ---------------------------------------------------------------------------------
@@ -289,6 +285,4 @@ void IntersectionFinderAccumulator::update(const NodeID from_node,
                                                          {from_node, via_edge});
 }
 
-} // namespace intersection
-} // namespace extractor
 } // namespace osrm
diff --git a/src/extractor/location_dependent_data.cpp b/src/extractor/location_dependent_data.cpp
index 828364e08..97edd10bc 100644
--- a/src/extractor/location_dependent_data.cpp
+++ b/src/extractor/location_dependent_data.cpp
@@ -14,9 +14,7 @@
 #include <fstream>
 #include <string>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 LocationDependentData::LocationDependentData(const std::vector<boost::filesystem::path> &file_paths)
@@ -275,5 +273,4 @@ std::vector<std::size_t> LocationDependentData::GetPropertyIndexes(const point_t
 
     return result;
 }
-} // namespace extractor
 } // namespace osrm
diff --git a/src/extractor/maneuver_override_relation_parser.cpp b/src/extractor/maneuver_override_relation_parser.cpp
index a9c697698..8c919e0c7 100644
--- a/src/extractor/maneuver_override_relation_parser.cpp
+++ b/src/extractor/maneuver_override_relation_parser.cpp
@@ -11,9 +11,7 @@
 #include <algorithm>
 #include <iterator>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 ManeuverOverrideRelationParser::ManeuverOverrideRelationParser() {}
@@ -136,5 +134,4 @@ ManeuverOverrideRelationParser::TryParse(const osmium::Relation &relation) const
     }
     return maneuver_override;
 }
-} // namespace extractor
 } // namespace osrm
diff --git a/src/extractor/node_based_graph_factory.cpp b/src/extractor/node_based_graph_factory.cpp
index 5edc44715..acac1a00a 100644
--- a/src/extractor/node_based_graph_factory.cpp
+++ b/src/extractor/node_based_graph_factory.cpp
@@ -10,9 +10,7 @@
 
 #include <set>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 NodeBasedGraphFactory::NodeBasedGraphFactory(
@@ -238,5 +236,4 @@ void NodeBasedGraphFactory::ReleaseOsmNodes()
     extractor::PackedOSMIDs().swap(osm_node_ids);
 }
 
-} // namespace extractor
 } // namespace osrm
diff --git a/src/extractor/raster_source.cpp b/src/extractor/raster_source.cpp
index 08a6bd324..041acd514 100644
--- a/src/extractor/raster_source.cpp
+++ b/src/extractor/raster_source.cpp
@@ -8,9 +8,7 @@
 
 #include <cmath>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 RasterSource::RasterSource(RasterGrid _raster_data,
@@ -169,5 +167,4 @@ RasterContainer::GetRasterInterpolateFromSource(unsigned int source_id, double l
 }
 
 RasterCache *RasterCache::g_instance = NULL;
-} // namespace extractor
 } // namespace osrm
diff --git a/src/extractor/restriction_graph.cpp b/src/extractor/restriction_graph.cpp
index aafcbcf6f..f3b205d3d 100644
--- a/src/extractor/restriction_graph.cpp
+++ b/src/extractor/restriction_graph.cpp
@@ -7,9 +7,7 @@
 
 #include <boost/range/algorithm/copy.hpp>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 namespace restriction_graph_details
@@ -284,5 +282,4 @@ RestrictionGraph::EdgeRange RestrictionGraph::GetEdges(RestrictionID id) const
                                       edges.begin() + node.edges_begin_idx + node.num_edges);
 }
 
-} // namespace extractor
 } // namespace osrm
diff --git a/src/extractor/restriction_parser.cpp b/src/extractor/restriction_parser.cpp
index 5daab9e74..606600011 100644
--- a/src/extractor/restriction_parser.cpp
+++ b/src/extractor/restriction_parser.cpp
@@ -13,9 +13,7 @@
 
 #include <algorithm>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 RestrictionParser::RestrictionParser(bool use_turn_restrictions_,
@@ -284,5 +282,4 @@ bool RestrictionParser::ShouldIgnoreRestriction(const std::string &except_tag_st
     }
     return restrictions.find(current_string) != restrictions.end();
 }
-} // namespace extractor
 } // namespace osrm
diff --git a/src/extractor/scripting_environment_lua.cpp b/src/extractor/scripting_environment_lua.cpp
index 9f54a91be..1919caa97 100644
--- a/src/extractor/scripting_environment_lua.cpp
+++ b/src/extractor/scripting_environment_lua.cpp
@@ -39,9 +39,7 @@ template <> struct is_container<osmium::Relation> : std::false_type
 };
 } // namespace sol
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 namespace
@@ -1251,5 +1249,4 @@ void LuaScriptingContext::ProcessWay(const osmium::Way &way,
     }
 }
 
-} // namespace extractor
 } // namespace osrm
diff --git a/src/extractor/suffix_table.cpp b/src/extractor/suffix_table.cpp
index a835562f9..aa5e0efb0 100644
--- a/src/extractor/suffix_table.cpp
+++ b/src/extractor/suffix_table.cpp
@@ -6,9 +6,7 @@
 
 #include <boost/algorithm/string.hpp>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 SuffixTable::SuffixTable(ScriptingEnvironment &scripting_environment)
@@ -33,5 +31,4 @@ bool SuffixTable::isSuffix(std::string_view possible_suffix) const
     return suffix_set.count(possible_suffix) > 0;
 }
 
-} /* namespace extractor */
 } /* namespace osrm */
diff --git a/src/extractor/turn_path_compressor.cpp b/src/extractor/turn_path_compressor.cpp
index 039b273ea..5c20915d8 100644
--- a/src/extractor/turn_path_compressor.cpp
+++ b/src/extractor/turn_path_compressor.cpp
@@ -5,9 +5,7 @@
 #include <algorithm>
 #include <boost/assert.hpp>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 TurnPathCompressor::TurnPathCompressor(std::vector<TurnRestriction> &restrictions,
@@ -160,5 +158,4 @@ void TurnPathCompressor::Compress(const NodeID from, const NodeID via, const Nod
     vias.erase(via);
 }
 
-} // namespace extractor
 } // namespace osrm
diff --git a/src/extractor/turn_path_filter.cpp b/src/extractor/turn_path_filter.cpp
index b26245792..fcea38ec8 100644
--- a/src/extractor/turn_path_filter.cpp
+++ b/src/extractor/turn_path_filter.cpp
@@ -7,9 +7,7 @@
 #include <algorithm>
 #include <boost/assert.hpp>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 template <typename T>
@@ -84,5 +82,4 @@ template std::vector<UnresolvedManeuverOverride>
 removeInvalidTurnPaths<>(std::vector<UnresolvedManeuverOverride>,
                          const util::NodeBasedDynamicGraph &);
 
-} // namespace extractor
 } // namespace osrm
diff --git a/src/extractor/way_restriction_map.cpp b/src/extractor/way_restriction_map.cpp
index bc1c90e09..0bd6a6c85 100644
--- a/src/extractor/way_restriction_map.cpp
+++ b/src/extractor/way_restriction_map.cpp
@@ -3,9 +3,7 @@
 #include <tuple>
 #include <utility>
 
-namespace osrm
-{
-namespace extractor
+namespace osrm::extractor
 {
 
 WayRestrictionMap::WayRestrictionMap(const RestrictionGraph &restriction_graph)
@@ -121,5 +119,4 @@ NodeID WayRestrictionMap::RemapIfRestrictionVia(const NodeID edge_based_target_n
     return edge_based_target_node;
 }
 
-} // namespace extractor
 } // namespace osrm
diff --git a/src/guidance/driveway_handler.cpp b/src/guidance/driveway_handler.cpp
index 4c7eee14a..18f40d567 100644
--- a/src/guidance/driveway_handler.cpp
+++ b/src/guidance/driveway_handler.cpp
@@ -2,9 +2,7 @@
 
 #include "util/assert.hpp"
 
-namespace osrm
-{
-namespace guidance
+namespace osrm::guidance
 {
 
 DrivewayHandler::DrivewayHandler(const util::NodeBasedDynamicGraph &node_based_graph,
@@ -91,5 +89,4 @@ Intersection DrivewayHandler::operator()(const NodeID nid,
     return intersection;
 }
 
-} // namespace guidance
 } // namespace osrm
diff --git a/src/guidance/guidance_processing.cpp b/src/guidance/guidance_processing.cpp
index cd24dabf0..5175295d3 100644
--- a/src/guidance/guidance_processing.cpp
+++ b/src/guidance/guidance_processing.cpp
@@ -13,9 +13,7 @@
 
 #include <thread>
 
-namespace osrm
-{
-namespace guidance
+namespace osrm::guidance
 {
 
 void annotateTurns(const util::NodeBasedDynamicGraph &node_based_graph,
@@ -349,5 +347,4 @@ void annotateTurns(const util::NodeBasedDynamicGraph &node_based_graph,
                 << bearing_class_hash.data.size() << " Bearing Classes";
 }
 
-} // namespace guidance
 } // namespace osrm
diff --git a/src/guidance/intersection_handler.cpp b/src/guidance/intersection_handler.cpp
index 80993fb89..73d523e99 100644
--- a/src/guidance/intersection_handler.cpp
+++ b/src/guidance/intersection_handler.cpp
@@ -14,9 +14,7 @@
 using EdgeData = osrm::util::NodeBasedDynamicGraph::EdgeData;
 using osrm::util::angularDeviation;
 
-namespace osrm
-{
-namespace guidance
+namespace osrm::guidance
 {
 
 namespace detail
@@ -488,5 +486,4 @@ bool IntersectionHandler::isSameName(const EdgeID source_edge_id, const EdgeID t
                                                   street_name_suffix_table); //
 }
 
-} // namespace guidance
 } // namespace osrm
diff --git a/src/guidance/motorway_handler.cpp b/src/guidance/motorway_handler.cpp
index 8fc0e4b2a..ad79d6670 100644
--- a/src/guidance/motorway_handler.cpp
+++ b/src/guidance/motorway_handler.cpp
@@ -13,9 +13,7 @@
 
 using osrm::util::angularDeviation;
 
-namespace osrm
-{
-namespace guidance
+namespace osrm::guidance
 {
 namespace
 {
@@ -562,5 +560,4 @@ Intersection MotorwayHandler::fallback(Intersection intersection) const
     return intersection;
 }
 
-} // namespace guidance
 } // namespace osrm
diff --git a/src/guidance/roundabout_handler.cpp b/src/guidance/roundabout_handler.cpp
index 13501fbfb..745771d49 100644
--- a/src/guidance/roundabout_handler.cpp
+++ b/src/guidance/roundabout_handler.cpp
@@ -15,9 +15,7 @@
 
 #include <boost/assert.hpp>
 
-namespace osrm
-{
-namespace guidance
+namespace osrm::guidance
 {
 
 RoundaboutHandler::RoundaboutHandler(
@@ -500,5 +498,4 @@ Intersection RoundaboutHandler::handleRoundabouts(const RoundaboutType roundabou
     return intersection;
 }
 
-} // namespace guidance
 } // namespace osrm
diff --git a/src/guidance/segregated_intersection_classification.cpp b/src/guidance/segregated_intersection_classification.cpp
index f9411a912..f3292b16c 100644
--- a/src/guidance/segregated_intersection_classification.cpp
+++ b/src/guidance/segregated_intersection_classification.cpp
@@ -6,9 +6,7 @@
 #include "util/coordinate_calculation.hpp"
 #include <set>
 
-namespace osrm
-{
-namespace guidance
+namespace osrm::guidance
 {
 
 // Maximum length in meters of an internal intersection edge
@@ -288,5 +286,4 @@ std::unordered_set<EdgeID> findSegregatedNodes(const extractor::NodeBasedGraphFa
     return segregated_edges;
 }
 
-} // namespace guidance
 } // namespace osrm
diff --git a/src/guidance/sliproad_handler.cpp b/src/guidance/sliproad_handler.cpp
index acc300978..5f4bea3b7 100644
--- a/src/guidance/sliproad_handler.cpp
+++ b/src/guidance/sliproad_handler.cpp
@@ -14,9 +14,7 @@
 
 using osrm::util::angularDeviation;
 
-namespace osrm
-{
-namespace guidance
+namespace osrm::guidance
 {
 
 SliproadHandler::SliproadHandler(const util::NodeBasedDynamicGraph &node_based_graph,
@@ -876,5 +874,4 @@ SliproadHandler::scaledThresholdByRoadClass(const double max_threshold,
     return scaled;
 }
 
-} // namespace guidance
 } // namespace osrm
diff --git a/src/guidance/suppress_mode_handler.cpp b/src/guidance/suppress_mode_handler.cpp
index a7ff5062c..a966dda59 100644
--- a/src/guidance/suppress_mode_handler.cpp
+++ b/src/guidance/suppress_mode_handler.cpp
@@ -4,9 +4,7 @@
 #include <algorithm>
 #include <iterator>
 
-namespace osrm
-{
-namespace guidance
+namespace osrm::guidance
 {
 
 SuppressModeHandler::SuppressModeHandler(
@@ -77,5 +75,4 @@ SuppressModeHandler::operator()(const NodeID, const EdgeID, Intersection interse
 
     return intersection;
 }
-} // namespace guidance
 } // namespace osrm
diff --git a/src/guidance/turn_analysis.cpp b/src/guidance/turn_analysis.cpp
index 57f68ec2b..a65af3cc4 100644
--- a/src/guidance/turn_analysis.cpp
+++ b/src/guidance/turn_analysis.cpp
@@ -10,9 +10,7 @@
 #include <unordered_set>
 #include <utility>
 
-namespace osrm
-{
-namespace guidance
+namespace osrm::guidance
 {
 
 using EdgeData = util::NodeBasedDynamicGraph::EdgeData;
@@ -199,5 +197,4 @@ Intersection TurnAnalysis::setTurnTypes(const NodeID node_prior_to_intersection,
     return intersection;
 }
 
-} // namespace guidance
 } // namespace osrm
diff --git a/src/guidance/turn_classification.cpp b/src/guidance/turn_classification.cpp
index edc0bd047..d192520f2 100644
--- a/src/guidance/turn_classification.cpp
+++ b/src/guidance/turn_classification.cpp
@@ -6,9 +6,7 @@
 #include <cstddef>
 #include <cstdint>
 
-namespace osrm
-{
-namespace guidance
+namespace osrm::guidance
 {
 
 std::pair<util::guidance::EntryClass, util::guidance::BearingClass>
@@ -93,5 +91,4 @@ classifyIntersection(Intersection intersection, const osrm::util::Coordinate &lo
     return std::make_pair(entry_class, bearing_class);
 }
 
-} // namespace guidance
 } // namespace osrm
diff --git a/src/guidance/turn_discovery.cpp b/src/guidance/turn_discovery.cpp
index d5138ecf1..e31ebb69f 100644
--- a/src/guidance/turn_discovery.cpp
+++ b/src/guidance/turn_discovery.cpp
@@ -7,11 +7,7 @@
 
 using osrm::util::angularDeviation;
 
-namespace osrm
-{
-namespace guidance
-{
-namespace lanes
+namespace osrm::guidance::lanes
 {
 
 bool findPreviousIntersection(const NodeID node_v,
@@ -145,6 +141,4 @@ bool findPreviousIntersection(const NodeID node_v,
     return true;
 }
 
-} // namespace lanes
-} // namespace guidance
 } // namespace osrm
diff --git a/src/guidance/turn_handler.cpp b/src/guidance/turn_handler.cpp
index f7b28132d..8b6e54929 100644
--- a/src/guidance/turn_handler.cpp
+++ b/src/guidance/turn_handler.cpp
@@ -69,9 +69,7 @@ InputIt findOutermostForkCandidate(const InputIt begin, const InputIt end)
 }
 } // namespace
 
-namespace osrm
-{
-namespace guidance
+namespace osrm::guidance
 {
 
 // a wrapper to handle road indices of forks at intersections
@@ -845,5 +843,4 @@ void TurnHandler::handleDistinctConflict(const EdgeID via_edge,
     }
 }
 
-} // namespace guidance
 } // namespace osrm
diff --git a/src/guidance/turn_lane_augmentation.cpp b/src/guidance/turn_lane_augmentation.cpp
index 07a8f7aa9..e4309303a 100644
--- a/src/guidance/turn_lane_augmentation.cpp
+++ b/src/guidance/turn_lane_augmentation.cpp
@@ -8,11 +8,7 @@
 #include <cstddef>
 #include <utility>
 
-namespace osrm
-{
-namespace guidance
-{
-namespace lanes
+namespace osrm::guidance::lanes
 {
 
 namespace
@@ -349,6 +345,4 @@ LaneDataVector handleNoneValueAtSimpleTurn(LaneDataVector lane_data,
     return lane_data;
 }
 
-} // namespace lanes
-} // namespace guidance
 } // namespace osrm
diff --git a/src/guidance/turn_lane_data.cpp b/src/guidance/turn_lane_data.cpp
index 76503c26e..98c3b0654 100644
--- a/src/guidance/turn_lane_data.cpp
+++ b/src/guidance/turn_lane_data.cpp
@@ -8,11 +8,7 @@
 #include <unordered_map>
 #include <utility>
 
-namespace osrm
-{
-namespace guidance
-{
-namespace lanes
+namespace osrm::guidance::lanes
 {
 namespace TurnLaneType = extractor::TurnLaneType;
 using TurnLaneDescription = extractor::TurnLaneDescription;
@@ -154,6 +150,4 @@ bool hasTag(const TurnLaneType::Mask tag, const LaneDataVector &data)
     return findTag(tag, data) != data.cend();
 }
 
-} // namespace lanes
-} // namespace guidance
 } // namespace osrm
diff --git a/src/guidance/turn_lane_handler.cpp b/src/guidance/turn_lane_handler.cpp
index 67297a0b4..460927b00 100644
--- a/src/guidance/turn_lane_handler.cpp
+++ b/src/guidance/turn_lane_handler.cpp
@@ -15,11 +15,7 @@
 
 using osrm::util::angularDeviation;
 
-namespace osrm
-{
-namespace guidance
-{
-namespace lanes
+namespace osrm::guidance::lanes
 {
 namespace TurnLaneType = extractor::TurnLaneType;
 using TurnLaneDescription = extractor::TurnLaneDescription;
@@ -813,6 +809,4 @@ Intersection TurnLaneHandler::handleSliproadTurn(Intersection intersection,
     return simpleMatchTuplesToTurns(std::move(intersection), lane_data, combined_id);
 }
 
-} // namespace lanes
-} // namespace guidance
 } // namespace osrm
diff --git a/src/guidance/turn_lane_matcher.cpp b/src/guidance/turn_lane_matcher.cpp
index 395c3d0f9..e338a2074 100644
--- a/src/guidance/turn_lane_matcher.cpp
+++ b/src/guidance/turn_lane_matcher.cpp
@@ -8,11 +8,7 @@
 
 using osrm::util::angularDeviation;
 
-namespace osrm
-{
-namespace guidance
-{
-namespace lanes
+namespace osrm::guidance::lanes
 {
 namespace TurnLaneType = extractor::TurnLaneType;
 
@@ -272,6 +268,4 @@ Intersection triviallyMatchLanesToTurns(Intersection intersection,
     return intersection;
 }
 
-} // namespace lanes
-} // namespace guidance
 } // namespace osrm
diff --git a/src/partitioner/bisection_graph_view.cpp b/src/partitioner/bisection_graph_view.cpp
index b71e43880..4a344f5d4 100644
--- a/src/partitioner/bisection_graph_view.cpp
+++ b/src/partitioner/bisection_graph_view.cpp
@@ -5,9 +5,7 @@
 
 #include <boost/assert.hpp>
 
-namespace osrm
-{
-namespace partitioner
+namespace osrm::partitioner
 {
 
 BisectionGraphView::BisectionGraphView(const BisectionGraph &bisection_graph_)
@@ -52,5 +50,4 @@ const BisectionGraphView::EdgeT &BisectionGraphView::Edge(const EdgeID eid) cons
     return bisection_graph.Edge(eid);
 }
 
-} // namespace partitioner
 } // namespace osrm
diff --git a/src/partitioner/bisection_to_partition.cpp b/src/partitioner/bisection_to_partition.cpp
index fe73b6ddd..ffca8f0ef 100644
--- a/src/partitioner/bisection_to_partition.cpp
+++ b/src/partitioner/bisection_to_partition.cpp
@@ -1,8 +1,6 @@
 #include "partitioner/bisection_to_partition.hpp"
 
-namespace osrm
-{
-namespace partitioner
+namespace osrm::partitioner
 {
 
 namespace
@@ -140,5 +138,4 @@ bisectionToPartition(const std::vector<BisectionID> &node_to_bisection_id,
 
     return std::make_tuple(std::move(partitions), std::move(num_cells));
 }
-} // namespace partitioner
 } // namespace osrm
diff --git a/src/partitioner/dinic_max_flow.cpp b/src/partitioner/dinic_max_flow.cpp
index a5def6a67..6a3654c63 100644
--- a/src/partitioner/dinic_max_flow.cpp
+++ b/src/partitioner/dinic_max_flow.cpp
@@ -8,9 +8,7 @@
 #include <set>
 #include <stack>
 
-namespace osrm
-{
-namespace partitioner
+namespace osrm::partitioner
 {
 
 namespace
@@ -309,5 +307,4 @@ bool DinicMaxFlow::Validate(const BisectionGraphView &view,
     return separated && in_range_source && in_range_sink;
 }
 
-} // namespace partitioner
 } // namespace osrm
diff --git a/src/partitioner/inertial_flow.cpp b/src/partitioner/inertial_flow.cpp
index 0d8aa425f..9e91f73e3 100644
--- a/src/partitioner/inertial_flow.cpp
+++ b/src/partitioner/inertial_flow.cpp
@@ -17,9 +17,7 @@
 #include <tbb/blocked_range.h>
 #include <tbb/parallel_for.h>
 
-namespace osrm
-{
-namespace partitioner
+namespace osrm::partitioner
 {
 namespace
 {
@@ -159,5 +157,4 @@ DinicMaxFlow::MinCut computeInertialFlowCut(const BisectionGraphView &view,
     return bestMinCut(view, num_slopes, source_sink_rate, balance);
 }
 
-} // namespace partitioner
 } // namespace osrm
diff --git a/src/partitioner/partitioner.cpp b/src/partitioner/partitioner.cpp
index bb37d52c5..4eddec260 100644
--- a/src/partitioner/partitioner.cpp
+++ b/src/partitioner/partitioner.cpp
@@ -31,9 +31,7 @@
 
 #include "util/timing_util.hpp"
 
-namespace osrm
-{
-namespace partitioner
+namespace osrm::partitioner
 {
 auto getGraphBisection(const PartitionerConfig &config)
 {
@@ -200,5 +198,4 @@ int Partitioner::Run(const PartitionerConfig &config)
     return 0;
 }
 
-} // namespace partitioner
 } // namespace osrm
diff --git a/src/partitioner/recursive_bisection.cpp b/src/partitioner/recursive_bisection.cpp
index 27a8f70ac..f3c8991ff 100644
--- a/src/partitioner/recursive_bisection.cpp
+++ b/src/partitioner/recursive_bisection.cpp
@@ -17,9 +17,7 @@
 #include <utility>
 #include <vector>
 
-namespace osrm
-{
-namespace partitioner
+namespace osrm::partitioner
 {
 
 RecursiveBisection::RecursiveBisection(BisectionGraph &bisection_graph_,
@@ -107,5 +105,4 @@ const std::vector<BisectionID> &RecursiveBisection::BisectionIDs() const
 
 std::uint32_t RecursiveBisection::SCCDepth() const { return internal_state.SCCDepth(); }
 
-} // namespace partitioner
 } // namespace osrm
diff --git a/src/partitioner/recursive_bisection_state.cpp b/src/partitioner/recursive_bisection_state.cpp
index 3ed488285..cb3d30a72 100644
--- a/src/partitioner/recursive_bisection_state.cpp
+++ b/src/partitioner/recursive_bisection_state.cpp
@@ -8,9 +8,7 @@
 #include <set>
 #include <unordered_map>
 
-namespace osrm
-{
-namespace partitioner
+namespace osrm::partitioner
 {
 
 RecursiveBisectionState::RecursiveBisectionState(BisectionGraph &bisection_graph_)
@@ -181,5 +179,4 @@ const std::vector<BisectionID> &RecursiveBisectionState::BisectionIDs() const
 
 std::uint32_t RecursiveBisectionState::SCCDepth() const { return scc_levels; }
 
-} // namespace partitioner
 } // namespace osrm
diff --git a/src/partitioner/renumber.cpp b/src/partitioner/renumber.cpp
index 9f3bee9d0..70d9bf558 100644
--- a/src/partitioner/renumber.cpp
+++ b/src/partitioner/renumber.cpp
@@ -2,9 +2,7 @@
 
 #include "util/permutation.hpp"
 
-namespace osrm
-{
-namespace partitioner
+namespace osrm::partitioner
 {
 namespace
 {
@@ -66,5 +64,4 @@ std::vector<std::uint32_t> makePermutation(const DynamicEdgeBasedGraph &graph,
 
     return util::orderingToPermutation(ordering);
 }
-} // namespace partitioner
 } // namespace osrm
diff --git a/src/partitioner/tarjan_graph_wrapper.cpp b/src/partitioner/tarjan_graph_wrapper.cpp
index 98c0b9584..79435fbb9 100644
--- a/src/partitioner/tarjan_graph_wrapper.cpp
+++ b/src/partitioner/tarjan_graph_wrapper.cpp
@@ -1,8 +1,6 @@
 #include "partitioner/tarjan_graph_wrapper.hpp"
 
-namespace osrm
-{
-namespace partitioner
+namespace osrm::partitioner
 {
 
 TarjanGraphWrapper::TarjanGraphWrapper(const BisectionGraph &bisection_graph_)
@@ -22,5 +20,4 @@ NodeID TarjanGraphWrapper::GetTarget(const EdgeID eid) const
     return bisection_graph.Edge(eid).target;
 }
 
-} // namespace partitioner
 } // namespace osrm
diff --git a/src/server/api/parameters_parser.cpp b/src/server/api/parameters_parser.cpp
index bfc4c2c20..795d62156 100644
--- a/src/server/api/parameters_parser.cpp
+++ b/src/server/api/parameters_parser.cpp
@@ -9,11 +9,7 @@
 
 #include <type_traits>
 
-namespace osrm
-{
-namespace server
-{
-namespace api
+namespace osrm::server::api
 {
 
 namespace detail
@@ -110,6 +106,4 @@ boost::optional<engine::api::TileParameters> parseParameters(std::string::iterat
     return detail::parseParameters<engine::api::TileParameters, TileParametersGrammar<>>(iter, end);
 }
 
-} // namespace api
-} // namespace server
 } // namespace osrm
diff --git a/src/server/api/url_parser.cpp b/src/server/api/url_parser.cpp
index 1a10f66c3..e244884ab 100644
--- a/src/server/api/url_parser.cpp
+++ b/src/server/api/url_parser.cpp
@@ -62,11 +62,7 @@ struct URLParser final : qi::grammar<Iterator, Into>
 
 } // namespace
 
-namespace osrm
-{
-namespace server
-{
-namespace api
+namespace osrm::server::api
 {
 
 boost::optional<ParsedURL> parseURL(std::string::iterator &iter, const std::string::iterator end)
@@ -93,6 +89,4 @@ boost::optional<ParsedURL> parseURL(std::string::iterator &iter, const std::stri
     return boost::none;
 }
 
-} // namespace api
-} // namespace server
 } // namespace osrm
diff --git a/src/server/connection.cpp b/src/server/connection.cpp
index 68e24c360..0e7eda0cb 100644
--- a/src/server/connection.cpp
+++ b/src/server/connection.cpp
@@ -9,9 +9,7 @@
 
 #include <vector>
 
-namespace osrm
-{
-namespace server
+namespace osrm::server
 {
 
 Connection::Connection(boost::asio::io_context &io_context, RequestHandler &handler)
@@ -220,5 +218,4 @@ std::vector<char> Connection::compress_buffers(const std::vector<char> &uncompre
 
     return compressed_data;
 }
-} // namespace server
 } // namespace osrm
diff --git a/src/server/http/reply.cpp b/src/server/http/reply.cpp
index 284d0c8fa..c7ff80094 100644
--- a/src/server/http/reply.cpp
+++ b/src/server/http/reply.cpp
@@ -2,11 +2,7 @@
 
 #include <string>
 
-namespace osrm
-{
-namespace server
-{
-namespace http
+namespace osrm::server::http
 {
 
 const char ok_html[] = "";
@@ -104,6 +100,4 @@ boost::asio::const_buffer reply::status_to_buffer(const reply::status_type statu
 }
 
 reply::reply() : status(ok) {}
-} // namespace http
-} // namespace server
 } // namespace osrm
diff --git a/src/server/request_handler.cpp b/src/server/request_handler.cpp
index f03ac3ac5..8f54d27c8 100644
--- a/src/server/request_handler.cpp
+++ b/src/server/request_handler.cpp
@@ -27,9 +27,7 @@
 #include <string>
 #include <thread>
 
-namespace osrm
-{
-namespace server
+namespace osrm::server
 {
 
 void RequestHandler::RegisterServiceHandler(
@@ -177,5 +175,4 @@ void RequestHandler::HandleRequest(const http::request &current_request, http::r
                               << ", uri: " << current_request.uri;
     }
 }
-} // namespace server
 } // namespace osrm
diff --git a/src/server/request_parser.cpp b/src/server/request_parser.cpp
index 3224bec31..211f33b00 100644
--- a/src/server/request_parser.cpp
+++ b/src/server/request_parser.cpp
@@ -8,9 +8,7 @@
 
 #include <string>
 
-namespace osrm
-{
-namespace server
+namespace osrm::server
 {
 
 RequestParser::RequestParser()
@@ -298,5 +296,4 @@ bool RequestParser::is_digit(const int character) const
 {
     return character >= '0' && character <= '9';
 }
-} // namespace server
 } // namespace osrm
diff --git a/src/server/service/match_service.cpp b/src/server/service/match_service.cpp
index c6132724a..4dfbe9e7b 100644
--- a/src/server/service/match_service.cpp
+++ b/src/server/service/match_service.cpp
@@ -8,11 +8,7 @@
 
 #include <boost/format.hpp>
 
-namespace osrm
-{
-namespace server
-{
-namespace service
+namespace osrm::server::service
 {
 namespace
 {
@@ -78,6 +74,4 @@ engine::Status MatchService::RunQuery(std::size_t prefix_length,
     }
     return BaseService::routing_machine.Match(*parameters, result);
 }
-} // namespace service
-} // namespace server
 } // namespace osrm
diff --git a/src/server/service/nearest_service.cpp b/src/server/service/nearest_service.cpp
index 1b316acd3..ac3bce3d9 100644
--- a/src/server/service/nearest_service.cpp
+++ b/src/server/service/nearest_service.cpp
@@ -8,11 +8,7 @@
 
 #include <boost/format.hpp>
 
-namespace osrm
-{
-namespace server
-{
-namespace service
+namespace osrm::server::service
 {
 
 namespace
@@ -72,6 +68,4 @@ engine::Status NearestService::RunQuery(std::size_t prefix_length,
     }
     return BaseService::routing_machine.Nearest(*parameters, result);
 }
-} // namespace service
-} // namespace server
 } // namespace osrm
diff --git a/src/server/service/route_service.cpp b/src/server/service/route_service.cpp
index 013fb4cf6..27a2c44aa 100644
--- a/src/server/service/route_service.cpp
+++ b/src/server/service/route_service.cpp
@@ -6,11 +6,7 @@
 
 #include "util/json_container.hpp"
 
-namespace osrm
-{
-namespace server
-{
-namespace service
+namespace osrm::server::service
 {
 namespace
 {
@@ -76,6 +72,4 @@ engine::Status RouteService::RunQuery(std::size_t prefix_length,
     }
     return BaseService::routing_machine.Route(*parameters, result);
 }
-} // namespace service
-} // namespace server
 } // namespace osrm
diff --git a/src/server/service/table_service.cpp b/src/server/service/table_service.cpp
index 5166be0b9..44fa1878a 100644
--- a/src/server/service/table_service.cpp
+++ b/src/server/service/table_service.cpp
@@ -7,11 +7,7 @@
 
 #include <boost/format.hpp>
 
-namespace osrm
-{
-namespace server
-{
-namespace service
+namespace osrm::server::service
 {
 
 namespace
@@ -107,6 +103,4 @@ engine::Status TableService::RunQuery(std::size_t prefix_length,
     }
     return BaseService::routing_machine.Table(*parameters, result);
 }
-} // namespace service
-} // namespace server
 } // namespace osrm
diff --git a/src/server/service/tile_service.cpp b/src/server/service/tile_service.cpp
index f518eac9f..2bc449d9b 100644
--- a/src/server/service/tile_service.cpp
+++ b/src/server/service/tile_service.cpp
@@ -8,11 +8,7 @@
 
 #include <boost/format.hpp>
 
-namespace osrm
-{
-namespace server
-{
-namespace service
+namespace osrm::server::service
 {
 
 engine::Status TileService::RunQuery(std::size_t prefix_length,
@@ -47,6 +43,4 @@ engine::Status TileService::RunQuery(std::size_t prefix_length,
     result = std::string();
     return BaseService::routing_machine.Tile(*parameters, result);
 }
-} // namespace service
-} // namespace server
 } // namespace osrm
diff --git a/src/server/service/trip_service.cpp b/src/server/service/trip_service.cpp
index 33f325e3b..68d910d87 100644
--- a/src/server/service/trip_service.cpp
+++ b/src/server/service/trip_service.cpp
@@ -8,11 +8,7 @@
 
 #include <boost/format.hpp>
 
-namespace osrm
-{
-namespace server
-{
-namespace service
+namespace osrm::server::service
 {
 namespace
 {
@@ -80,6 +76,4 @@ engine::Status TripService::RunQuery(std::size_t prefix_length,
     }
     return BaseService::routing_machine.Trip(*parameters, result);
 }
-} // namespace service
-} // namespace server
 } // namespace osrm
diff --git a/src/server/service_handler.cpp b/src/server/service_handler.cpp
index 1dfe817bf..3ed47ba49 100644
--- a/src/server/service_handler.cpp
+++ b/src/server/service_handler.cpp
@@ -12,9 +12,7 @@
 
 #include <memory>
 
-namespace osrm
-{
-namespace server
+namespace osrm::server
 {
 ServiceHandler::ServiceHandler(osrm::EngineConfig &config) : routing_machine(config)
 {
@@ -51,5 +49,4 @@ engine::Status ServiceHandler::RunQuery(api::ParsedURL parsed_url,
 
     return service->RunQuery(parsed_url.prefix_length, parsed_url.query, result);
 }
-} // namespace server
 } // namespace osrm
diff --git a/src/storage/io_config.cpp b/src/storage/io_config.cpp
index cd05d2d76..c64081cc1 100644
--- a/src/storage/io_config.cpp
+++ b/src/storage/io_config.cpp
@@ -6,9 +6,7 @@
 #include <boost/filesystem/operations.hpp>
 #include <boost/filesystem/path.hpp>
 
-namespace osrm
-{
-namespace storage
+namespace osrm::storage
 {
 
 namespace fs = boost::filesystem;
@@ -40,5 +38,4 @@ std::vector<std::string> IOConfig::GetMissingFiles() const
     }
     return missingFiles;
 }
-} // namespace storage
 } // namespace osrm
diff --git a/src/storage/storage.cpp b/src/storage/storage.cpp
index 4aba706a0..13a411e09 100644
--- a/src/storage/storage.cpp
+++ b/src/storage/storage.cpp
@@ -36,9 +36,7 @@
 #include <new>
 #include <string>
 
-namespace osrm
-{
-namespace storage
+namespace osrm::storage
 {
 namespace
 {
@@ -587,5 +585,4 @@ void Storage::PopulateUpdatableData(const SharedDataIndex &index)
         }
     }
 }
-} // namespace storage
 } // namespace osrm
diff --git a/src/tools/components.cpp b/src/tools/components.cpp
index 7431bbca5..1a1f16ed4 100644
--- a/src/tools/components.cpp
+++ b/src/tools/components.cpp
@@ -25,9 +25,7 @@
 #include <string>
 #include <vector>
 
-namespace osrm
-{
-namespace tools
+namespace osrm::tools
 {
 
 using TarjanGraph = util::StaticGraph<void>;
@@ -103,7 +101,6 @@ struct FeatureWriter
 };
 
 //
-} // namespace tools
 } // namespace osrm
 
 int main(int argc, char *argv[])
diff --git a/src/tools/routed.cpp b/src/tools/routed.cpp
index 7aec139a7..7d250dcb0 100644
--- a/src/tools/routed.cpp
+++ b/src/tools/routed.cpp
@@ -52,9 +52,7 @@ const static unsigned INIT_OK_START_ENGINE = 0;
 const static unsigned INIT_OK_DO_NOT_START_ENGINE = 1;
 const static unsigned INIT_FAILED = -1;
 
-namespace osrm
-{
-namespace engine
+namespace osrm::engine
 {
 std::istream &operator>>(std::istream &in, EngineConfig::Algorithm &algorithm)
 {
@@ -70,7 +68,6 @@ std::istream &operator>>(std::istream &in, EngineConfig::Algorithm &algorithm)
         throw util::RuntimeError(token, ErrorCode::UnknownAlgorithm, SOURCE_REF);
     return in;
 }
-} // namespace engine
 } // namespace osrm
 
 // generate boost::program_options object for the routing part
diff --git a/src/updater/csv_source.cpp b/src/updater/csv_source.cpp
index fe13a7477..49f0efb4f 100644
--- a/src/updater/csv_source.cpp
+++ b/src/updater/csv_source.cpp
@@ -25,11 +25,7 @@ namespace
 namespace qi = boost::spirit::qi;
 }
 
-namespace osrm
-{
-namespace updater
-{
-namespace csv
+namespace osrm::updater::csv
 {
 SegmentLookupTable readSegmentValues(const std::vector<std::string> &paths)
 {
@@ -63,6 +59,4 @@ TurnLookupTable readTurnValues(const std::vector<std::string> &paths)
                                                qi::double_ >> -(',' >> qi::double_));
     return parser(paths);
 }
-} // namespace csv
-} // namespace updater
 } // namespace osrm
diff --git a/src/updater/updater.cpp b/src/updater/updater.cpp
index 2ae0354c3..40eb3d80f 100644
--- a/src/updater/updater.cpp
+++ b/src/updater/updater.cpp
@@ -61,9 +61,7 @@ template <typename T1, typename T2> struct hash<std::tuple<T1, T2>>
 };
 } // namespace std
 
-namespace osrm
-{
-namespace updater
+namespace osrm::updater
 {
 namespace
 {
@@ -843,5 +841,4 @@ Updater::LoadAndUpdateEdgeExpandedGraph(std::vector<extractor::EdgeBasedEdge> &e
     util::Log() << "Done reading edges in " << TIMER_MSEC(load_edges) << "ms.";
     return number_of_edge_based_nodes;
 }
-} // namespace updater
 } // namespace osrm
diff --git a/src/util/conditional_restrictions.cpp b/src/util/conditional_restrictions.cpp
index b748f1162..d7c138b92 100644
--- a/src/util/conditional_restrictions.cpp
+++ b/src/util/conditional_restrictions.cpp
@@ -4,9 +4,7 @@
 #include <boost/spirit/include/phoenix.hpp>
 #include <boost/spirit/include/qi.hpp>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 #ifndef NDEBUG
@@ -16,15 +14,12 @@ inline std::ostream &operator<<(std::ostream &stream, const ConditionalRestricti
     return stream << restriction.value << "=" << restriction.condition;
 }
 #endif
-} // namespace util
 } // namespace osrm
 
 BOOST_FUSION_ADAPT_STRUCT(osrm::util::ConditionalRestriction,
                           (std::string, value)(std::string, condition))
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 namespace detail
 {
@@ -91,5 +86,4 @@ std::vector<ConditionalRestriction> ParseConditionalRestrictions(const std::stri
     return result;
 }
 
-} // namespace util
 } // namespace osrm
diff --git a/src/util/coordinate.cpp b/src/util/coordinate.cpp
index e9082399c..42c80b28b 100644
--- a/src/util/coordinate.cpp
+++ b/src/util/coordinate.cpp
@@ -12,9 +12,7 @@
 #include <iostream>
 #include <limits>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 bool Coordinate::IsValid() const
@@ -42,5 +40,4 @@ bool operator==(const FloatCoordinate lhs, const FloatCoordinate rhs)
 
 bool operator!=(const Coordinate lhs, const Coordinate rhs) { return !(lhs == rhs); }
 bool operator!=(const FloatCoordinate lhs, const FloatCoordinate rhs) { return !(lhs == rhs); }
-} // namespace util
 } // namespace osrm
diff --git a/src/util/coordinate_calculation.cpp b/src/util/coordinate_calculation.cpp
index ec95a382a..9c062fb56 100644
--- a/src/util/coordinate_calculation.cpp
+++ b/src/util/coordinate_calculation.cpp
@@ -12,12 +12,7 @@
 #include <limits>
 #include <utility>
 
-namespace osrm
-{
-namespace util
-{
-
-namespace coordinate_calculation
+namespace osrm::util::coordinate_calculation
 {
 
 namespace
@@ -419,6 +414,4 @@ double computeArea(const std::vector<Coordinate> &polygon)
     return area / 2.;
 }
 
-} // namespace coordinate_calculation
-} // namespace util
 } // namespace osrm
diff --git a/src/util/exception.cpp b/src/util/exception.cpp
index 2788deace..a157ddb0c 100644
--- a/src/util/exception.cpp
+++ b/src/util/exception.cpp
@@ -11,12 +11,9 @@
 // this, the compiler will copy the vtable and RTTI into every .o file that
 // #includes the header, bloating .o file sizes and increasing link times.
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 void exception::anchor() const {}
 void RuntimeError::anchor() const {}
-} // namespace util
 } // namespace osrm
diff --git a/src/util/fingerprint.cpp b/src/util/fingerprint.cpp
index 303d318aa..7daf61a78 100644
--- a/src/util/fingerprint.cpp
+++ b/src/util/fingerprint.cpp
@@ -11,9 +11,7 @@
 #include <algorithm>
 #include <string>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 /**
@@ -91,5 +89,4 @@ bool FingerPrint::IsDataCompatible(const FingerPrint &other) const
     return IsValid() && other.major_version == major_version &&
            other.minor_version == minor_version;
 }
-} // namespace util
 } // namespace osrm
diff --git a/src/util/geojson_debug_policies.cpp b/src/util/geojson_debug_policies.cpp
index 0cd898808..62cf546ec 100644
--- a/src/util/geojson_debug_policies.cpp
+++ b/src/util/geojson_debug_policies.cpp
@@ -4,9 +4,7 @@
 
 #include <algorithm>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 //----------------------------------------------------------------
@@ -68,5 +66,4 @@ CoordinateVectorToLineString::operator()(const std::vector<util::Coordinate> &in
     return makeFeature("LineString", std::move(coordinates), properties);
 }
 
-} /* namespace util */
 } /* namespace osrm */
diff --git a/src/util/guidance/bearing_class.cpp b/src/util/guidance/bearing_class.cpp
index 6e49466a5..56869b480 100644
--- a/src/util/guidance/bearing_class.cpp
+++ b/src/util/guidance/bearing_class.cpp
@@ -4,11 +4,7 @@
 #include <algorithm>
 #include <boost/assert.hpp>
 
-namespace osrm
-{
-namespace util
-{
-namespace guidance
+namespace osrm::util::guidance
 {
 
 BearingClass::BearingClass() { available_bearings.reserve(10); }
@@ -77,6 +73,4 @@ std::size_t BearingClass::findMatchingBearing(const double bearing) const
     return std::distance(available_bearings.begin(), max_element);
 }
 
-} // namespace guidance
-} // namespace util
 } // namespace osrm
diff --git a/src/util/guidance/entry_class.cpp b/src/util/guidance/entry_class.cpp
index 34232f244..d85b92140 100644
--- a/src/util/guidance/entry_class.cpp
+++ b/src/util/guidance/entry_class.cpp
@@ -4,11 +4,7 @@
 
 #include <climits>
 
-namespace osrm
-{
-namespace util
-{
-namespace guidance
+namespace osrm::util::guidance
 {
 
 bool EntryClass::activate(std::uint32_t index)
@@ -36,6 +32,4 @@ bool EntryClass::operator<(const EntryClass &other) const
     return enabled_entries_flags < other.enabled_entries_flags;
 }
 
-} // namespace guidance
-} // namespace util
 } // namespace osrm
diff --git a/src/util/guidance/turn_lanes.cpp b/src/util/guidance/turn_lanes.cpp
index cad86c059..46091aa43 100644
--- a/src/util/guidance/turn_lanes.cpp
+++ b/src/util/guidance/turn_lanes.cpp
@@ -6,11 +6,7 @@
 
 #include <boost/assert.hpp>
 
-namespace osrm
-{
-namespace util
-{
-namespace guidance
+namespace osrm::util::guidance
 {
 LaneTuple::LaneTuple() : lanes_in_turn(0), first_lane_from_the_right(INVALID_LANEID)
 {
@@ -36,6 +32,4 @@ bool LaneTupleIdPair::operator==(const LaneTupleIdPair &other) const
     return other.first == first && other.second == second;
 }
 
-} // namespace guidance
-} // namespace util
 } // namespace osrm
diff --git a/src/util/log.cpp b/src/util/log.cpp
index 45042e72e..765ed8e44 100644
--- a/src/util/log.cpp
+++ b/src/util/log.cpp
@@ -7,9 +7,7 @@
 #include <mutex>
 #include <string>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 namespace
@@ -163,5 +161,4 @@ UnbufferedLog::UnbufferedLog(LogLevel level_)
 {
     stream.flags(std::ios_base::unitbuf);
 }
-} // namespace util
 } // namespace osrm
diff --git a/src/util/opening_hours.cpp b/src/util/opening_hours.cpp
index e3ce583d9..cd3cb94cc 100644
--- a/src/util/opening_hours.cpp
+++ b/src/util/opening_hours.cpp
@@ -10,9 +10,7 @@
 #include <iomanip>
 #include <iterator>
 
-namespace osrm
-{
-namespace util
+namespace osrm::util
 {
 
 #ifndef NDEBUG
@@ -431,5 +429,4 @@ bool CheckOpeningHours(const std::vector<OpeningHours> &input, const struct tm &
     return is_open;
 }
 
-} // namespace util
 } // namespace osrm
diff --git a/src/util/timed_histogram.cpp b/src/util/timed_histogram.cpp
index 92657e70c..a015cca49 100644
--- a/src/util/timed_histogram.cpp
+++ b/src/util/timed_histogram.cpp
@@ -1,12 +1,6 @@
 #include "util/timed_histogram.hpp"
 
-namespace osrm
-{
-namespace util
-{
-namespace detail
+namespace osrm::util::detail
 {
 std::atomic_uint operation = {0};
-}
-} // namespace util
 } // namespace osrm
diff --git a/src/util/timezones.cpp b/src/util/timezones.cpp
index 948f34855..6cd2867d5 100644
--- a/src/util/timezones.cpp
+++ b/src/util/timezones.cpp
@@ -21,9 +21,7 @@
 // Function loads time zone shape polygons, computes a zone local time for utc_time,
 // creates a lookup R-tree and returns a lambda function that maps a point
 // to the corresponding local time
-namespace osrm
-{
-namespace updater
+namespace osrm::updater
 {
 
 Timezoner::Timezoner(const char geojson[], std::time_t utc_time_now)
@@ -171,5 +169,4 @@ boost::optional<struct tm> Timezoner::operator()(const point_t &point) const
     }
     return boost::none;
 }
-} // namespace updater
 } // namespace osrm
diff --git a/unit_tests/contractor/contracted_edge_container.cpp b/unit_tests/contractor/contracted_edge_container.cpp
index e6c228abe..603c04b63 100644
--- a/unit_tests/contractor/contracted_edge_container.cpp
+++ b/unit_tests/contractor/contracted_edge_container.cpp
@@ -7,9 +7,7 @@
 using namespace osrm;
 using namespace osrm::contractor;
 
-namespace osrm
-{
-namespace contractor
+namespace osrm::contractor
 {
 
 bool operator!=(const QueryEdge &lhs, const QueryEdge &rhs) { return !(lhs == rhs); }
@@ -27,7 +25,6 @@ std::ostream &operator<<(std::ostream &out, const QueryEdge &edge)
     out << "{" << edge.source << ", " << edge.target << ", " << edge.data << "}";
     return out;
 }
-} // namespace contractor
 } // namespace osrm
 
 BOOST_AUTO_TEST_SUITE(contracted_edge_container)
diff --git a/unit_tests/contractor/helper.hpp b/unit_tests/contractor/helper.hpp
index 27a4a8d51..b598fc867 100644
--- a/unit_tests/contractor/helper.hpp
+++ b/unit_tests/contractor/helper.hpp
@@ -3,9 +3,7 @@
 
 #include "contractor/contractor_graph.hpp"
 
-namespace osrm
-{
-namespace unit_test
+namespace osrm::unit_test
 {
 
 using TestEdge = std::tuple<unsigned, unsigned, int>;
@@ -38,7 +36,6 @@ inline contractor::ContractorGraph makeGraph(const std::vector<TestEdge> &edges)
 
     return contractor::ContractorGraph{max_id + 1, input_edges};
 }
-} // namespace unit_test
 } // namespace osrm
 
 #endif
diff --git a/unit_tests/engine/offline_facade.cpp b/unit_tests/engine/offline_facade.cpp
index afe1c7253..cfde4e91c 100644
--- a/unit_tests/engine/offline_facade.cpp
+++ b/unit_tests/engine/offline_facade.cpp
@@ -5,21 +5,13 @@
 
 #include <boost/test/unit_test.hpp>
 
-namespace osrm
+namespace osrm::engine
 {
-namespace engine
-{
-namespace routing_algorithms
-{
-
-// Declare offline data facade algorithm
-namespace offline
+namespace routing_algorithms::offline
 {
 struct Algorithm final
 {
 };
-} // namespace offline
-
 } // namespace routing_algorithms
 
 // Define engine data for offline data facade
@@ -332,9 +324,7 @@ class ContiguousInternalMemoryDataFacade<routing_algorithms::offline::Algorithm>
 } // namespace datafacade
 
 // Fallback to MLD algorithm: requires from data facade MLD specific members
-namespace routing_algorithms
-{
-namespace offline
+namespace routing_algorithms::offline
 {
 
 template <typename PhantomT>
@@ -371,10 +361,8 @@ void unpackPath(const FacadeT &facade,
     mld::unpackPath(facade, packed_path_begin, packed_path_end, endpoints, unpacked_path);
 }
 
-} // namespace offline
 } // namespace routing_algorithms
 
-} // namespace engine
 } // namespace osrm
 
 BOOST_AUTO_TEST_SUITE(offline_facade)
diff --git a/unit_tests/mocks/mock_datafacade.hpp b/unit_tests/mocks/mock_datafacade.hpp
index 81471835b..a393f98eb 100644
--- a/unit_tests/mocks/mock_datafacade.hpp
+++ b/unit_tests/mocks/mock_datafacade.hpp
@@ -19,9 +19,7 @@
 #include "util/guidance/entry_class.hpp"
 #include "util/typedefs.hpp"
 
-namespace osrm
-{
-namespace test
+namespace osrm::test
 {
 
 class MockBaseDataFacade : public engine::datafacade::BaseDataFacade
@@ -260,7 +258,6 @@ class MockDataFacade final : public MockBaseDataFacade, public MockAlgorithmData
 {
 };
 
-} // namespace test
 } // namespace osrm
 
 #endif // MOCK_DATAFACADE_HPP
diff --git a/unit_tests/mocks/mock_scripting_environment.hpp b/unit_tests/mocks/mock_scripting_environment.hpp
index a34a03cc0..66530534e 100644
--- a/unit_tests/mocks/mock_scripting_environment.hpp
+++ b/unit_tests/mocks/mock_scripting_environment.hpp
@@ -11,10 +11,7 @@
 #include <utility>
 #include <vector>
 
-namespace osrm
-{
-
-namespace test
+namespace osrm::test
 {
 
 // a mock implementation of the scripting environment doing exactly nothing
@@ -50,7 +47,6 @@ class MockScriptingEnvironment : public extractor::ScriptingEnvironment
     bool HasLocationDependentData() const override { return false; };
 };
 
-} // namespace test
 } // namespace osrm
 
 #endif // MOCK_SCRIPTING_ENVIRONMENT_HPP_
diff --git a/unit_tests/server/parameters_io.hpp b/unit_tests/server/parameters_io.hpp
index e7930aa2a..ed1243650 100644
--- a/unit_tests/server/parameters_io.hpp
+++ b/unit_tests/server/parameters_io.hpp
@@ -7,9 +7,7 @@
 
 #include <ostream>
 
-namespace osrm
-{
-namespace engine
+namespace osrm::engine
 {
 namespace api
 {
@@ -60,7 +58,6 @@ inline std::ostream &operator<<(std::ostream &out, Approach approach)
     out << static_cast<int>(approach);
     return out;
 }
-} // namespace engine
 } // namespace osrm
 
 #endif
diff --git a/unit_tests/server/url_parser.cpp b/unit_tests/server/url_parser.cpp
index 0796cbe7b..d2f83f99b 100644
--- a/unit_tests/server/url_parser.cpp
+++ b/unit_tests/server/url_parser.cpp
@@ -3,11 +3,7 @@
 #include <fstream>
 
 // needed for BOOST_CHECK_EQUAL
-namespace osrm
-{
-namespace server
-{
-namespace api
+namespace osrm::server::api
 {
 std::ostream &operator<<(std::ostream &out, const osrm::server::api::ParsedURL &url)
 {
@@ -15,8 +11,6 @@ std::ostream &operator<<(std::ostream &out, const osrm::server::api::ParsedURL &
 
     return out;
 }
-} // namespace api
-} // namespace server
 } // namespace osrm
 
 #include <boost/test/test_tools.hpp>