NHTSA wants cyan lights to mark self-driving cars — but won't require them
A new federal proposal would let automakers add cyan exterior lights so police and paramedics can tell when nobody is actually driving.
What happened: The National Highway Traffic Safety Administration has drafted a rule proposing cyan-colored exterior lights as the official US signal that a car is driving itself. The idea originated with Mercedes-Benz, which tested it in California for two years alongside its hands-free DRIVE PILOT system, and was independently endorsed by the SAE engineering standards body. China released a near-identical draft days earlier, picking turquoise instead of cyan, for vehicles starting in 2028. Under NHTSA's version, the lights would be optional, not mandatory.
Why it matters: As driverless cars spread, police officers and paramedics increasingly encounter vehicles with no one in the driver's seat. Without a clear signal, responders can't easily tell whether that's intentional autonomous operation or a medical emergency where a driver has gone missing. A standardized light color is meant to remove that guesswork during traffic stops, crashes, or breakdowns.
How it works, plainly: Under the draft rule, cyan lights would switch on only while the car is driving itself and switch off the instant a human takes control. They'd need to be visible from every angle, with markers on the front, sides and rear, mounted at least 15 inches above the ground, and all lights would have to turn on and off together so there's no ambiguity about the car's status.
The rollout: The proposal also quietly loosens some existing safety rules for cars built without steering wheels, such as removing the requirement that turn signals auto-cancel after a steering wheel turn, since some robotaxis have none. The full draft opens for 30 days of public comment under docket NHTSA-2026-1519. Electrek's reporting notes these rule changes follow scrutiny of a steering-wheel-less robotaxi that NHTSA investigated after it was deployed before meeting current standards, raising questions about whose interests the rule changes serve.