diff --git a/planning/behavior_path_planner/include/behavior_path_planner/utils/utils.hpp b/planning/behavior_path_planner/include/behavior_path_planner/utils/utils.hpp
index bda91138d30cf..01caa699c5f94 100644
--- a/planning/behavior_path_planner/include/behavior_path_planner/utils/utils.hpp
+++ b/planning/behavior_path_planner/include/behavior_path_planner/utils/utils.hpp
@@ -131,8 +131,6 @@ double l2Norm(const Vector3 vector);
 
 double getDistanceToEndOfLane(const Pose & current_pose, const lanelet::ConstLanelets & lanelets);
 
-bool isRedTrafficSignal(const TrafficSignalStamped & traffic_signal);
-
 std::pair<lanelet::Id, double> getDistanceToNextTrafficLight(
   const Pose & current_pose, const lanelet::ConstLanelets & lanelets);