/control/command/hazard_lights_cmd#
Specifications#
| Item | Value |
|---|---|
| Last Updated | 2026-01-21 |
| Interface Type | topic |
| Interface Name | /control/command/hazard_lights_cmd |
| Data Type | autoware_vehicle_msgs/msg/HazardLightsCommand |
| Rate [Hz] | 10 or N/A |
| QoS Reliability | reliable |
| QoS Durability | volatile or transient_local |
Description#
Send the hazard lights change command to the vehicle. The command is ENABLE or DISABLE.
It is recommended to set QoS to transient_local and publish only when the command changes, but currently many implementations publish the command periodically.
Therefore, ensure consistency across the entire system.
Message#
The stamp field is the command sent time. In the case of periodic publication, use the latest time, not the last command change.
For the command field, use the valid values listed above. The NO_COMMAND value can be used internally by programs, but will never be sent as a topic.
Errors#
Invalid command: If the vehicle interface receives an undefined command, it is ignored and a diagnostic error is reported.
Support#
This interface is required. If the vehicle does not have hazard lights, always ignore the command.
Limitations#
None.
Use Cases#
- Control the vehicle for autonomous driving.
- Relay commands from the operator.
Requirement#
- Support sending the hazard lights command to the vehicle.
- Report the error as diagnostics if an unsupported or unknown command is sent.
Design#
Separation from turn indicators: Hazard lights and turn indicators are defined in separate interfaces to allow independent state management. For example, an autonomous stack might request "Turn Left" for routing, but a safety system might simultaneously request "Hazard Enable" due to an emergency. This simplifies the logic because an autonomous stack and safety system no longer have to worry about their states being overwritten by each other's commands.
Priority logic: The vehicle interface must prioritize HazardLightsCommand.ENABLE over any TurnIndicatorsCommand. This ensures safety signals (hazards) always take precedence over navigation signals.
History#
| Date | Description |
|---|---|
| 2026-01-21 | First release in the new format. |