NHTSA Proposes Cyan Lights for Self-Driving Cars

The National Highway Traffic Safety Administration has proposed a specific color of light to signal that an autonomous system is operating a vehicle. The proposal, issued recently, outlines the use of cyan-colored lights as a marker for cars driving themselves. This move aims to resolve a long-standing debate over how driverless cars should visually indicate that no human is at the wheel. Previous suggestions have included flashing text or audio alerts, but regulators are now moving toward a unified lighting standard.

The proposed changes to Federal Motor Vehicle Safety Standard No. 108 are designed to both streamline rules for vehicles without drivers and standardize how self-driving cars communicate with other road users. The agency specifically proposes cyan marker lamps to signal when an automated driving system is active. The choice of cyan is intended to avoid confusion with existing safety lights. The automotive industry already uses red for brakes, amber for turn signals, white for headlights, and flashing blue and red for emergency vehicles. A distinct blue-green light would occupy a visual gap without clashing with these established colors.

There is some precedent for using this color. Mercedes-Benz previously received state-level approval for turquoise lights on its Level 3 Drive Pilot vehicles. The automaker has since moved away from that idea in favor of a different system. However, the National Highway Traffic Safety Administration aims to create a national standard for such signals. This would allow robotaxi operators, including Waymo, Nuro, and Zoox, as well as automakers like General Motors and Mercedes, to adopt a uniform approach.

Under the proposed rule, the installation of these lights would remain optional for manufacturers. However, the agency is creating official federal standards regarding their color, brightness, and location. By doing so, regulators want to ensure that any manufacturer choosing to add such lights uses a consistent and legal setup. This prevents a confusing mix of different colors and signals appearing on the road.

The proposal also addresses outdated equipment requirements. Current rules demand physical hazard switches, manual beam shifters, and turn levers inside vehicles. The agency is proposing to remove these requirements for autonomous vehicles. Additionally, the agency is updating the 12.8-volt testing standard. This change allows manufacturers to build around modern LED architectures without navigating administrative hurdles. The agency is also considering removing requirements regarding the placement of high-beam lights relative to low-beam lights.

This update aligns with a broader effort by the Department of Transportation to streamline the deployment of autonomous vehicles. The government intends to make it easier to build cars without traditional controls like steering wheels and pedals. These controls are typically found in vehicles operated by human drivers.

Despite the push to update rules for the future, regulators are still enforcing current safety standards. Last month, the agency opened an audit query into the Tesla Cybercab. The inquiry seeks to examine the process and technical data Tesla used to certify the vehicle. The inquiry relates to the absence of design features such as sideview mirrors, pedals, and steering wheels, which are required under current federal standards.