Cyan Lights Mark Driverless Cars

The US federal government has proposed a specific blue-green color to identify driverless cars on public roads. This move aims to solve a long-standing debate in the automotive industry regarding how autonomous vehicles should visually communicate their status to other drivers and pedestrians.

The National Highway Traffic Safety Administration, or NHTSA, released proposed changes to Federal Motor Vehicle Safety Standard No. 108. This standard currently governs vehicle lighting. The new rules seek to simplify regulations for cars without human drivers while creating a unified way for robotaxis to signal their operational status.

The agency selected cyan because other colors are already in use. Red, amber, white, and flashing blue or red lights indicate braking, turning, headlights, or emergency vehicles. By using a distinct hue, the new lights would fill a visual gap without confusing traffic. The proposal notes that these lamps would clearly tell law enforcement and other road users when an automated system is in control.

Some automakers have experimented with similar ideas. Mercedes-Benz received state approval for turquoise lights on its Level 3 vehicles, though it later shifted to a different system. NHTSA now wants a national standard that companies like Waymo, Nuro, and Zoox, as well as manufacturers like GM and Mercedes, can all adopt consistently.

Under the new rules, installing the cyan lights would remain optional for makers. However, if a company chooses to add them, the federal government would dictate the exact color, brightness, and placement. This approach prevents a patchwork of different signals across various brands and ensures legal consistency.

The proposal also removes outdated requirements that do not apply to vehicles without human operators. Current rules mandate physical hazard switches, manual beam shifters, and turn levers. NHTSA plans to eliminate these demands. It also intends to update testing standards for 12.8-volt systems to accommodate modern LED technology and may drop rules about the vertical placement of high-beam lights.

These changes support a broader effort by the Department of Transportation to accelerate the rollout of autonomous vehicles. The goal is to make it easier for manufacturers to build cars without traditional controls like steering wheels and pedals. Despite this forward-looking approach, regulators are still enforcing current rules. Last month, NHTSA launched an audit of the Tesla Cybercab to review the technical data used for its certification, specifically regarding the absence of sideview mirrors, pedals, and a steering wheel.