diff --git a/RoutingAlgorithms/ShortestPathRouting.h b/RoutingAlgorithms/ShortestPathRouting.h
index c1d231be8..d73a1352f 100644
--- a/RoutingAlgorithms/ShortestPathRouting.h
+++ b/RoutingAlgorithms/ShortestPathRouting.h
@@ -259,9 +259,9 @@ public:
             }
 
             BOOST_ASSERT_MSG(
-                temporary_packed_path1.empty() &&
-                temporary_packed_path2.empty(),
-                "tempory packed paths not empty"
+                !temporary_packed_path1.empty() ||
+                !temporary_packed_path2.empty(),
+                "tempory packed paths empty"
             );
 
             //Plug paths together, s.t. end of packed path is begin of temporary packed path