Traffic Light

Role

Judgement whether a vehicle can go into an intersection or not by traffic light status, and planning a velocity of the stop if necessary. This module is designed for rule-based velocity decision that is easy for developers to design its behavior. It generates proper velocity for traffic light scene.

Limitations

This module allows developers to design STOP/GO in traffic light module using specific rules. Due to the property of rule-based planning, the algorithm is greatly depends on object detection and perception accuracy considering traffic light. Also, this module only handles STOP/Go at traffic light scene, so rushing or quick decision according to traffic condition is future work.

Activation Timing

This module is activated when there is traffic light in ego lane.

Algorithm

1. Obtains a traffic light mapped to the route and a stop line correspond to the traffic light from a map information.

   • If a corresponding traffic light signal have never been found, it treats as a signal to pass.

   • If a corresponding traffic light signal is found but timed out, it treats as a signal to stop.

2. Uses the highest reliability one of the traffic light recognition result and if the color of that was not green or corresponding arrow signal, generates a stop point.

   • If an elapsed time to receive stop signal is less than stop_time_hysteresis, it treats as a signal to pass. This feature is to prevent chattering.

3. When vehicle current velocity is

   • higher than yellow_light_stop_velocity m/s ⇒ pass judge(using next slide formula)

   • lower than yellow_light_stop_velocity m/s ⇒ stop

4. When it to be judged that vehicle can’t stop before stop line, autoware chooses one of the following behaviors

   • “can pass through” stop line during yellow lamp => pass

   • “can’t pass through” stop line during yellow lamp => emergency stop

Dilemma Zone

• yellow lamp line

  It’s called “yellow lamp line” which shows the distance traveled by the vehicle during yellow lamp.

• dilemma zone

  It’s called “dilemma zone” which satisfies following conditions:

  • vehicle can’t pass through stop line during yellow lamp.(right side of the yellow lamp line)

  • vehicle can’t stop under deceleration and jerk limit.(left side of the pass judge curve)

    ⇒emergency stop(relax deceleration and jerk limitation in order to observe the traffic regulation)

• optional zone

  It’s called “optional zone” which satisfies following conditions:

  • vehicle can pass through stop line during yellow lamp.(left side of the yellow lamp line)

  • vehicle can stop under deceleration and jerk limit.(right side of the pass judge curve)

    ⇒ stop(autoware selects the safety choice)

Module Parameters

Flowchart

@startuml
title modifyPathVelocity
start

:calc stop point and insert index;

:find offset segment;

:calculate stop pose;

:calculate distance to stop line;

if (state is APPROACH) then (yes)
  :set stop velocity;
  if (distance to stop point is below singed dead line length(-2[m])) then (yes)
    :change state to GO_OUT;
    stop
  elseif (no stop signal) then (yes)
    :change previous state to PASS;
    stop
  elseif (not pass through) then (yes)
    :insert stop pose;
    :change previous state to STOP;
    stop
  else(no)
    stop
  endif
elseif(state is GO_OUT) then (yes)
  if (signed arc length to stop line is more than restart length(1[m])) then (yes)
    :change state to APPROACH;
  endif
  stop
else(no)
  stop
endif

@enduml

Known Limits

• tbd.

Changelog for package autoware_behavior_velocity_traffic_light_module

0.44.0 (2025-04-18)

• Merge remote-tracking branch 'origin/main' into humble
• feat(traffic_light): restart suppression at traffic light stop_point (#10451)
  • feat: restart suppression at traffic light stop_point

  * style(pre-commit): autofix ---------Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]\@users.noreply.github.com>

• Contributors: Ryohsuke Mitsudome, eiki

0.43.0 (2025-03-21)

• Merge remote-tracking branch 'origin/main' into chore/bump-version-0.43
• chore: rename from [autoware.universe]{.title-ref} to [autoware_universe]{.title-ref} (#10306)
• fix(behavior_velocity_planner): planning factor integration (#10292)
  • fix: blind_spot
  • fix: crosswalk
  • fix: detection_area
  • fix: intersection
  • fix: no_drivable_lane
  • fix: no_stopping_area
  • fix: run_out
  • fix: stop_line
  • fix: traffic_light
  • fix: virtual_traffic_light

  * fix: walk_way ---------

• fix(stopline, traffic_light): fix planning factor distance value (#10245)
• feat(Autoware_planning_factor_interface): replace tier4_msgs with autoware_internal_msgs (#10204)
• Contributors: Hayato Mizushima, Mamoru Sobue, Satoshi OTA, Yutaka Kondo, 心刚

0.42.0 (2025-03-03)

• Merge remote-tracking branch 'origin/main' into tmp/bot/bump_version_base
• feat(autoware_utils): replace autoware_universe_utils with autoware_utils (#10191)
• feat!: replace tier4_planning_msgs/PathWithLaneId with autoware_internal_planning_msgs/PathWithLaneId (#10023)
• feat(autoware_behavior_velocity_traffic_light_module): adjust velocity threshold for ensure stop at yellow light (#10064)
• feat(planning_test_manager): abstract message-specific functions (#9882)
  • abstract message-specific functions
  • include necessary header
  • adapt velocity_smoother to new test manager
  • adapt behavior_velocity_planner to new test manager
  • adapt path_optimizer to new test manager
  • fix output subscription
  • adapt behavior_path_planner to new test manager
  • adapt scenario_selector to new test manager
  • adapt freespace_planner to new test manager
  • adapt planning_validator to new test manager
  • adapt obstacle_stop_planner to new test manager
  • adapt obstacle_cruise_planner to new test manager
  • disable test for freespace_planner
  • adapt behavior_velocity_crosswalk_module to new test manager
  • adapt behavior_path_lane_change_module to new test manager
  • adapt behavior_path_avoidance_by_lane_change_module to new test manager
  • adapt behavior_path_dynamic_obstacle_avoidance_module to new test manager
  • adapt behavior_path_external_request_lane_change_module to new test manager
  • adapt behavior_path_side_shift_module to new test manager
  • adapt behavior_path_static_obstacle_avoidance_module to new test manager
  • adapt path_smoother to new test manager
  • adapt behavior_velocity_blind_spot_module to new test manager
  • adapt behavior_velocity_detection_area_module to new test manager
  • adapt behavior_velocity_intersection_module to new test manager
  • adapt behavior_velocity_no_stopping_area_module to new test manager
  • adapt behavior_velocity_run_out_module to new test manager
  • adapt behavior_velocity_stop_line_module to new test manager
  • adapt behavior_velocity_traffic_light_module to new test manager
  • adapt behavior_velocity_virtual_traffic_light_module to new test manager
  • adapt behavior_velocity_walkway_module to new test manager
  • adapt motion_velocity_planner_node_universe to new test manager
  • include necessary headers

  * Odometries -> Odometry ---------Co-authored-by: Takayuki Murooka <<takayuki5168@gmail.com>>

• Contributors: Fumiya Watanabe, Mitsuhiro Sakamoto, Ryohsuke Mitsudome, Tomoya Kimura, 心刚

0.41.2 (2025-02-19)

• chore: bump version to 0.41.1 (#10088)
• Contributors: Ryohsuke Mitsudome

0.41.1 (2025-02-10)

0.41.0 (2025-01-29)

• Merge remote-tracking branch 'origin/main' into tmp/bot/bump_version_base
• chore(planning): move package directory for planning factor interface (#9948)
  • chore: add new package for planning factor interface
  • chore(surround_obstacle_checker): update include file
  • chore(obstacle_stop_planner): update include file
  • chore(obstacle_cruise_planner): update include file
  • chore(motion_velocity_planner): update include file
  • chore(bpp): update include file
  • chore(bvp-common): update include file
  • chore(blind_spot): update include file
  • chore(crosswalk): update include file
  • chore(detection_area): update include file
  • chore(intersection): update include file
  • chore(no_drivable_area): update include file
  • chore(no_stopping_area): update include file
  • chore(occlusion_spot): update include file
  • chore(run_out): update include file
  • chore(speed_bump): update include file
  • chore(stop_line): update include file
  • chore(template_module): update include file
  • chore(traffic_light): update include file
  • chore(vtl): update include file
  • chore(walkway): update include file

  * chore(motion_utils): remove factor interface ---------

• feat(behavior_velocity_planner)!: remove velocity_factor completely (#9943)
  • feat(behavior_velocity_planner)!: remove velocity_factor completely

  * minimize diff ---------

• feat(planning_factor)!: remove velocity_factor, steering_factor and introduce planning_factor (#9927) Co-authored-by: Satoshi OTA <<44889564+satoshi-ota@users.noreply.github.com>> Co-authored-by: Ryohsuke Mitsudome <<43976834+mitsudome-r@users.noreply.github.com>> Co-authored-by: satoshi-ota <<satoshi.ota928@gmail.com>>
• feat(behavior_velocity_modules): add node test (#9790)
  • feat(behavior_velocity_crosswalk): add node test
  • fix
  • feat(behavior_velocity_xxx_module): add node test
  • fix
  • fix
  • fix
  • fix

  * change directory tests -> test ---------

• refactor(behavior_velocity_planner_common): add behavior_velocity_rtc_interface and move RTC-related implementation (#9799)
  • split into planer_common and rtc_interface

  * Update planning/behavior_velocity_planner/autoware_behavior_velocity_planner_common/include/autoware/behavior_velocity_planner_common/scene_module_interface.hpp Co-authored-by: Mamoru Sobue <<mamoru.sobue@tier4.jp>> * Update planning/behavior_velocity_planner/autoware_behavior_velocity_rtc_interface/include/autoware/behavior_velocity_rtc_interface/scene_module_interface_with_rtc.hpp Co-authored-by: Mamoru Sobue <<mamoru.sobue@tier4.jp>> * fix ——

  Co-authored-by: Mamoru Sobue <<mamoru.sobue@tier4.jp>>

• Contributors: Fumiya Watanabe, Mamoru Sobue, Satoshi OTA, Takayuki Murooka

0.40.0 (2024-12-12)

• Merge branch 'main' into release-0.40.0
• Revert "chore(package.xml): bump version to 0.39.0 (#9587)" This reverts commit c9f0f2688c57b0f657f5c1f28f036a970682e7f5.
• fix: fix ticket links in CHANGELOG.rst (#9588)
• chore(package.xml): bump version to 0.39.0 (#9587)
  • chore(package.xml): bump version to 0.39.0
  • fix: fix ticket links in CHANGELOG.rst

  * fix: remove unnecessary diff ---------Co-authored-by: Yutaka Kondo <<yutaka.kondo@youtalk.jp>>

• fix: fix ticket links in CHANGELOG.rst (#9588)
• fix(cpplint): include what you use - planning (#9570)
• ci(pre-commit): autoupdate (#8949) Co-authored-by: M. Fatih Cırıt <<mfc@autoware.org>>
• feat(behavior_velocity_planner)!: remove stop_reason (#9452)
• refactor(autoware_behavior_velocity_planner_common,autoware_behavior_velocity_planner): separate param files (#9470)
  • refactor(autoware_behavior_velocity_planner_common,autoware_behavior_velocity_planner): separate param files

  * Update planning/autoware_static_centerline_generator/test/test_static_centerline_generator.test.py Co-authored-by: Kyoichi Sugahara <<32741405+kyoichi-sugahara@users.noreply.github.com>> * fix ——

  Co-authored-by: Kyoichi Sugahara <<32741405+kyoichi-sugahara@users.noreply.github.com>>

• 0.39.0
• update changelog
• fix: fix ticket links to point to https://github.com/autowarefoundation/autoware_universe (#9304)
• refactor(traffic_light_utils): prefix package and namespace with autoware (#9251)
• feat(behavior_velocity_planner): replace first_stop_path_point_index (#9296)
  • feat(behavior_velocity_planner): replace first_stop_path_point_index
  • add const

  * Update planning/behavior_velocity_planner/autoware_behavior_velocity_traffic_light_module/src/scene.cpp Co-authored-by: Kosuke Takeuchi <<kosuke.tnp@gmail.com>> * Update planning/behavior_velocity_planner/autoware_behavior_velocity_planner/src/planner_manager.cpp Co-authored-by: Kosuke Takeuchi <<kosuke.tnp@gmail.com>> ---------Co-authored-by: Kosuke Takeuchi <<kosuke.tnp@gmail.com>>

• fix: fix ticket links to point to https://github.com/autowarefoundation/autoware_universe (#9304)
• chore(package.xml): bump version to 0.38.0 (#9266) (#9284)
  • unify package.xml version to 0.37.0
  • remove system_monitor/CHANGELOG.rst
  • add changelog

  * 0.38.0

• Contributors: Esteve Fernandez, Fumiya Watanabe, M. Fatih Cırıt, Mamoru Sobue, Ryohsuke Mitsudome, Yukinari Hisaki, Yutaka Kondo, awf-autoware-bot[bot]

0.39.0 (2024-11-25)

• fix: fix ticket links to point to https://github.com/autowarefoundation/autoware_universe (#9304)
• fix: fix ticket links to point to https://github.com/autowarefoundation/autoware_universe (#9304)
• chore(package.xml): bump version to 0.38.0 (#9266) (#9284)
  • unify package.xml version to 0.37.0
  • remove system_monitor/CHANGELOG.rst
  • add changelog

  * 0.38.0

• Contributors: Esteve Fernandez, Yutaka Kondo

0.38.0 (2024-11-08)

• unify package.xml version to 0.37.0
• test(traffic_light): write test for utils (#9046)
  • refactor: separate utils file
  • refactor: utils function output
  • test: write test for utils

  * chore: add doxygen ---------

• fix(behavior_velocity_traffic_light): make dilemma_zone_plotter.py executable (#8684)
• feat(traffic_light): add dilemma_zone_plotter.py (#8638)
  • feat(traffic_light): add dilemma_zone_plotter.py
  • fix typo

  * fix typo ---------

• fix(behavior_velocity_planner): fix cppcheck warnings of virtualCallInConstructor (#8376) Co-authored-by: Ryuta Kambe <<ryuta.kambe@tier4.jp>>
• fix(autoware_behavior_velocity_traffic_light_module): fix uninitMemberVar (#8317) fix:funinitMemberVar
• feat: add [autoware_]{.title-ref} prefix to [lanelet2_extension]{.title-ref} (#7640)
• refactor(universe_utils/motion_utils)!: add autoware namespace (#7594)
• refactor(motion_utils)!: add autoware prefix and include dir (#7539) refactor(motion_utils): add autoware prefix and include dir
• feat(autoware_universe_utils)!: rename from tier4_autoware_utils (#7538) Co-authored-by: kosuke55 <<kosuke.tnp@gmail.com>>
• chore(behavior_velocity_planner): move packages (#7526)
• Contributors: Fumiya Watanabe, Kosuke Takeuchi, Satoshi OTA, Takayuki Murooka, Yutaka Kondo, kobayu858, taisa1

0.26.0 (2024-04-03)