diff --git a/RoutingAlgorithms/BasicRoutingInterface.h b/RoutingAlgorithms/BasicRoutingInterface.h
index 637b0d3cf..4290bc0c3 100644
--- a/RoutingAlgorithms/BasicRoutingInterface.h
+++ b/RoutingAlgorithms/BasicRoutingInterface.h
@@ -306,6 +306,11 @@ public:
             packed_path.push_back(current_node_id);
         }
     }
+
+    int ComputeEdgeOffset(const PhantomNode & phantom) const {
+        return phantom.weight1 + (phantom.isBidirected() ? phantom.weight2 : 0);
+    }
+
 };
 
 #endif /* BASICROUTINGINTERFACE_H_ */