autoware_dummy_traffic_light_publisher

Purpose

Publish dummy traffic light signals for simulation environments where a traffic light recognition module is not available.

Modes

Mode	Description
standalone	Cycles through Green -> Yellow -> Red for all traffic lights found in the vector map.
empty	Publishes an empty TrafficLightGroupArray (no traffic light groups).
fixed	Publishes a single fixed color (fixed_color) for all traffic lights found in the vector map.

To assign different signals per traffic light ID, use pass-through instead (see below); fixed mode intentionally applies one color to every light.

Pass-through

When a message is received on the input topic (~/input/traffic_signals), the node relays it as-is instead of generating its own signals. If no new input arrives within passthrough_timeout seconds, the node falls back to its configured mode.

Interface

Subscriptions

Topic	Type	Description
~/input/vector_map	autoware_map_msgs/msg/LaneletMapBin	Lanelet2 map to extract traffic light regulatory element IDs.
~/input/traffic_signals	autoware_perception_msgs/msg/TrafficLightGroupArray	External traffic light signals for pass-through.

Publications

Topic	Type	Description
~/output/traffic_signals	autoware_perception_msgs/msg/TrafficLightGroupArray	Generated or relayed traffic light signals.

Parameters

Parameter	Type	Default	Description
mode	string	"empty"	Operating mode: "standalone", "empty" or "fixed".
publish_rate	double	10.0	Publishing frequency [Hz].
green_duration	double	30.0	Duration of the green phase [s] (standalone mode).
yellow_duration	double	3.0	Duration of the yellow phase [s] (standalone mode).
red_duration	double	30.0	Duration of the red phase [s] (standalone mode).
passthrough_timeout	double	1.0	Time after last input before falling back to the configured mode [s].
fixed_color	string	"red"	Color published in fixed mode: "green", "yellow" or "red".

Usage

Launch

bash ros2 launch autoware_dummy_traffic_light_publisher dummy_traffic_light_publisher.launch.xml

To override the mode:

bash ros2 launch autoware_dummy_traffic_light_publisher dummy_traffic_light_publisher.launch.xml mode:=standalone

To publish a fixed color for all traffic lights:

bash ros2 launch autoware_dummy_traffic_light_publisher dummy_traffic_light_publisher.launch.xml mode:=fixed fixed_color:=green

Design and extension tactics

This package separates concerns into three layers:

Layer	Class	Role
ROS I/O	DummyTrafficLightPublisherNode	Subscriptions (take()), timer, publisher, vector map parsing.
Message assembly	DummyTrafficLight	Pass-through judgment, traffic light ID management, TrafficLightGroupArray construction.
Signal generation	TrafficLightCycle	Phase computation (Green/Yellow/Red) from elapsed time and TrafficLightElement output.

When extending, modify only the layer that owns the responsibility:

• Adding arrow shapes, flashing patterns, or new signal types — change TrafficLightCycle. It owns TrafficLightElement construction. Node and DummyTrafficLight are unaffected.
• Per-intersection or per-ID signal control — change DummyTrafficLight. It maps IDs to elements. TrafficLightCycle and Node are unaffected.
• Adding new input sources or output topics — change DummyTrafficLightPublisherNode. Logic layers are unaffected.

Run node directly

The parameters have no in-code defaults, so a parameter file must be provided (e.g. the packaged config/dummy_traffic_light_publisher.param.yaml):

bash ros2 run autoware_dummy_traffic_light_publisher autoware_dummy_traffic_light_publisher_node --ros-args \ --params-file $(ros2 pkg prefix --share autoware_dummy_traffic_light_publisher)/config/dummy_traffic_light_publisher.param.yaml \ -p mode:=standalone \ -r ~/input/vector_map:=/map/vector_map \ -r ~/input/traffic_signals:=/simulator/input/traffic_signals \ -r ~/output/traffic_signals:=/perception/traffic_light_recognition/traffic_signals