What Do Green Lights on Cars Mean?

Green flashing lights on a vehicle are used by specific first responders and emergency personnel, depending on the region:

• Volunteer Firefighters & EMS (US & Canada): In several US states (such as New York) and Canadian provinces (such as Ontario), volunteer firefighters and emergency medical technicians use flashing green lights on their personal vehicles to signal that they are actively responding to an emergency call.

• On-Call Doctors (UK & Commonwealth): In the UK, doctors responding to urgent medical emergencies are authorized to use green flashing lights on their personal or service vehicles to request right-of-way.

• Incident Command Vehicles: Under standardized emergency management protocols (such as ICS/FEMA standards), a steady or flashing green light on a parked vehicle marks it as the active Incident Command Post at a major emergency site.

• Private Security & Airport Patrols: In various jurisdictions, private security companies, mobile safety patrols, and airport ground control vehicles use green or green-and-amber light bars to identify non-police security vehicles.