NHTSA wants cyan lights to mark cars that drive themselves

How should a car tell everyone around it that nobody is driving? The US National Highway Traffic Safety Administration (NHTSA) has proposed an answer: a cyan, or blue-green, light. The idea is part of a proposed update to Federal Motor Vehicle Safety Standard (FMVSS) No. 108, the rule that covers lamps and reflectors on US vehicles. The notice is listed in the Federal Register, and The Verge first reported it.

What the cyan lamps would do

NHTSA calls them ADS marker lamps, where ADS stands for automated driving system. They would switch on only when the vehicle is driving itself with no expectation that someone inside is watching the road. That is the robotaxi case, and the case of Level 3 systems while they are engaged.

The lamps would be optional. NHTSA says it does not have enough evidence to require them on every self-driving vehicle. Instead, the rule would set a standard "if equipped":

• Four to eight lamps: one or two each on the front, the rear and each side.
• Mounted at least 15 inches (38 cm) above the ground.
• Steady burning when on. NHTSA is asking for comments on whether flashing should also be allowed.
• Only on ADS-equipped vehicles. Cars without automated driving could not fit them.

The specifications are largely based on the industry standard SAE J3134. NHTSA says cyan was chosen partly because it is easy to tell apart from the blue lights used by police. There is a precedent: Mercedes-Benz won state approval for turquoise lights on its Level 3 Drive Pilot system.

Rules for cars with no steering wheel

The other half of the proposal cuts requirements that make little sense in a vehicle with no driver controls. For those vehicles only, NHTSA would no longer require manually operated turn-signal, hazard and high-beam switches. Some dashboard warning-light ("telltale") requirements would also be narrowed. The hazard telltale would stay, because passengers may want to know when the car has switched its hazards on.

Two changes apply more widely. NHTSA wants to update the test voltage for integral-beam headlamps and remove the rules for vertical headlamp arrangements, giving designers more freedom with LED lighting.

What happens next

This is a notice of proposed rulemaking, not a final rule. Comments are open until 25 November 2026, and NHTSA will then decide whether to adopt, change or drop the ideas. Robotaxi fleets are expanding fast, including Waymo's planned move into Madrid. A single, recognisable signal would give police, pedestrians and other drivers one simple cue. Without one, every company could invent its own.

If you're more interested in the driver-assist features you can buy today, our dash cam buying guide explains how to record what happens on the road around you.