Clamp durations to 0 rather than 1

include/engine/routing_algorithms/routing_base.hpp

@@ -405,7 +405,7 @@ template <class DataFacadeT, class Derived> class BasicRoutingInterface
             // node to the first turn would be the same as from end to end of a segment,
             // which is obviously incorrect and not ideal...
             unpacked_path.front().duration_until_turn =
-                std::max(unpacked_path.front().duration_until_turn - source_weight, 1);
+                std::max(unpacked_path.front().duration_until_turn - source_weight, 0);
         }
 
         // there is no equivalent to a node-based node in an edge-expanded graph.