diff --git a/include/engine/search_engine_data.hpp b/include/engine/search_engine_data.hpp
index 16ffa25b1..7c885343f 100644
--- a/include/engine/search_engine_data.hpp
+++ b/include/engine/search_engine_data.hpp
@@ -45,19 +45,19 @@ template <> struct SearchEngineData<routing_algorithms::ch::Algorithm>
                                                 ManyToManyHeapData,
                                                 util::UnorderedMapStorage<NodeID, int>>;
 
-    using SearchEngineHeapPtr = boost::thread_specific_ptr<QueryHeap>;
+    using SearchEngineHeapPtr = std::unique_ptr<QueryHeap>;
 
-    using ManyToManyHeapPtr = boost::thread_specific_ptr<ManyToManyQueryHeap>;
+    using ManyToManyHeapPtr = std::unique_ptr<ManyToManyQueryHeap>;
 
-    static SearchEngineHeapPtr forward_heap_1;
-    static SearchEngineHeapPtr reverse_heap_1;
-    static SearchEngineHeapPtr forward_heap_2;
-    static SearchEngineHeapPtr reverse_heap_2;
-    static SearchEngineHeapPtr forward_heap_3;
-    static SearchEngineHeapPtr reverse_heap_3;
-    static ManyToManyHeapPtr many_to_many_heap;
-    static SearchEngineHeapPtr map_matching_forward_heap_1;
-    static SearchEngineHeapPtr map_matching_reverse_heap_1;
+    static thread_local SearchEngineHeapPtr forward_heap_1;
+    static thread_local SearchEngineHeapPtr reverse_heap_1;
+    static thread_local SearchEngineHeapPtr forward_heap_2;
+    static thread_local SearchEngineHeapPtr reverse_heap_2;
+    static thread_local SearchEngineHeapPtr forward_heap_3;
+    static thread_local SearchEngineHeapPtr reverse_heap_3;
+    static thread_local ManyToManyHeapPtr many_to_many_heap;
+    static thread_local SearchEngineHeapPtr map_matching_forward_heap_1;
+    static thread_local SearchEngineHeapPtr map_matching_reverse_heap_1;
 
     void InitializeOrClearMapMatchingThreadLocalStorage(unsigned number_of_nodes);
 
@@ -127,16 +127,16 @@ template <> struct SearchEngineData<routing_algorithms::mld::Algorithm>
                                                  MapMatchingMultiLayerDijkstraHeapData,
                                                  util::TwoLevelStorage<NodeID, int>>;
 
-    using SearchEngineHeapPtr = boost::thread_specific_ptr<QueryHeap>;
-    using ManyToManyHeapPtr = boost::thread_specific_ptr<ManyToManyQueryHeap>;
-    using MapMatchingHeapPtr = boost::thread_specific_ptr<MapMatchingQueryHeap>;
+    using SearchEngineHeapPtr = std::unique_ptr<QueryHeap>;
+    using ManyToManyHeapPtr = std::unique_ptr<ManyToManyQueryHeap>;
+    using MapMatchingHeapPtr = std::unique_ptr<MapMatchingQueryHeap>;
 
-    static SearchEngineHeapPtr forward_heap_1;
-    static SearchEngineHeapPtr reverse_heap_1;
-    static MapMatchingHeapPtr map_matching_forward_heap_1;
-    static MapMatchingHeapPtr map_matching_reverse_heap_1;
+    static thread_local SearchEngineHeapPtr forward_heap_1;
+    static thread_local SearchEngineHeapPtr reverse_heap_1;
+    static thread_local MapMatchingHeapPtr map_matching_forward_heap_1;
+    static thread_local MapMatchingHeapPtr map_matching_reverse_heap_1;
 
-    static ManyToManyHeapPtr many_to_many_heap;
+    static thread_local ManyToManyHeapPtr many_to_many_heap;
 
     void InitializeOrClearFirstThreadLocalStorage(unsigned number_of_nodes,
                                                   unsigned number_of_boundary_nodes);
diff --git a/include/util/pool_allocator.hpp b/include/util/pool_allocator.hpp
index e106c575f..7d6e03714 100644
--- a/include/util/pool_allocator.hpp
+++ b/include/util/pool_allocator.hpp
@@ -59,7 +59,6 @@ public:
 
     ~MemoryManager()
     {
-       // std::lock_guard<std::mutex> lock(mutex_);
         for (auto block : blocks_)
         {
             std::free(block);
diff --git a/src/engine/search_engine_data.cpp b/src/engine/search_engine_data.cpp
index dd1a053e0..1eb497a46 100644
--- a/src/engine/search_engine_data.cpp
+++ b/src/engine/search_engine_data.cpp
@@ -5,16 +5,16 @@ namespace osrm::engine
 
 // CH heaps
 using CH = routing_algorithms::ch::Algorithm;
-SearchEngineData<CH>::SearchEngineHeapPtr SearchEngineData<CH>::forward_heap_1;
-SearchEngineData<CH>::SearchEngineHeapPtr SearchEngineData<CH>::reverse_heap_1;
-SearchEngineData<CH>::SearchEngineHeapPtr SearchEngineData<CH>::forward_heap_2;
-SearchEngineData<CH>::SearchEngineHeapPtr SearchEngineData<CH>::reverse_heap_2;
-SearchEngineData<CH>::SearchEngineHeapPtr SearchEngineData<CH>::forward_heap_3;
-SearchEngineData<CH>::SearchEngineHeapPtr SearchEngineData<CH>::reverse_heap_3;
-SearchEngineData<CH>::SearchEngineHeapPtr SearchEngineData<CH>::map_matching_forward_heap_1;
-SearchEngineData<CH>::SearchEngineHeapPtr SearchEngineData<CH>::map_matching_reverse_heap_1;
+thread_local SearchEngineData<CH>::SearchEngineHeapPtr SearchEngineData<CH>::forward_heap_1;
+thread_local SearchEngineData<CH>::SearchEngineHeapPtr SearchEngineData<CH>::reverse_heap_1;
+thread_local SearchEngineData<CH>::SearchEngineHeapPtr SearchEngineData<CH>::forward_heap_2;
+thread_local SearchEngineData<CH>::SearchEngineHeapPtr SearchEngineData<CH>::reverse_heap_2;
+thread_local SearchEngineData<CH>::SearchEngineHeapPtr SearchEngineData<CH>::forward_heap_3;
+thread_local SearchEngineData<CH>::SearchEngineHeapPtr SearchEngineData<CH>::reverse_heap_3;
+thread_local SearchEngineData<CH>::SearchEngineHeapPtr SearchEngineData<CH>::map_matching_forward_heap_1;
+thread_local SearchEngineData<CH>::SearchEngineHeapPtr SearchEngineData<CH>::map_matching_reverse_heap_1;
 
-SearchEngineData<CH>::ManyToManyHeapPtr SearchEngineData<CH>::many_to_many_heap;
+thread_local SearchEngineData<CH>::ManyToManyHeapPtr SearchEngineData<CH>::many_to_many_heap;
 
 void SearchEngineData<CH>::InitializeOrClearMapMatchingThreadLocalStorage(unsigned number_of_nodes)
 {
@@ -114,11 +114,11 @@ void SearchEngineData<CH>::InitializeOrClearManyToManyThreadLocalStorage(unsigne
 
 // MLD
 using MLD = routing_algorithms::mld::Algorithm;
-SearchEngineData<MLD>::SearchEngineHeapPtr SearchEngineData<MLD>::forward_heap_1;
-SearchEngineData<MLD>::SearchEngineHeapPtr SearchEngineData<MLD>::reverse_heap_1;
-SearchEngineData<MLD>::MapMatchingHeapPtr SearchEngineData<MLD>::map_matching_forward_heap_1;
-SearchEngineData<MLD>::MapMatchingHeapPtr SearchEngineData<MLD>::map_matching_reverse_heap_1;
-SearchEngineData<MLD>::ManyToManyHeapPtr SearchEngineData<MLD>::many_to_many_heap;
+thread_local SearchEngineData<MLD>::SearchEngineHeapPtr SearchEngineData<MLD>::forward_heap_1;
+thread_local SearchEngineData<MLD>::SearchEngineHeapPtr SearchEngineData<MLD>::reverse_heap_1;
+thread_local SearchEngineData<MLD>::MapMatchingHeapPtr SearchEngineData<MLD>::map_matching_forward_heap_1;
+thread_local SearchEngineData<MLD>::MapMatchingHeapPtr SearchEngineData<MLD>::map_matching_reverse_heap_1;
+thread_local SearchEngineData<MLD>::ManyToManyHeapPtr SearchEngineData<MLD>::many_to_many_heap;
 
 void SearchEngineData<MLD>::InitializeOrClearMapMatchingThreadLocalStorage(
     unsigned number_of_nodes, unsigned number_of_boundary_nodes)