Federal Agencies Push Cyan Lights For Driverless Cars

The National Highway Traffic Safety Administration has proposed a new federal standard requiring driverless vehicles to use distinct cyan-colored marker lights. This move aims to give law enforcement and other motorists a clear, consistent visual cue that a vehicle is being operated by an automated system rather than a human driver. By establishing this specific color, the agency hopes to resolve long-standing debates about how robotaxis should signal their presence to the surrounding traffic.

The proposal is part of a broader update to Federal Motor Vehicle Safety Standard No. 108, which currently governs vehicle lighting. NHTSA is rewriting sections of the rule to accommodate autonomous designs that lack traditional interior controls. The agency argues that existing lighting colors, such as red, amber, white, and flashing blue or red, are already heavily utilized for brake lights, turn signals, headlights, and emergency vehicles. Cyan was selected because it fills a visual gap in the spectrum, allowing a driverless car to be identified without confusing other road users who rely on those established colors for different purposes.

While the idea of colored lights for autonomous vehicles is not entirely new, it has not yet been standardized at the federal level. Mercedes-Benz previously received state-level approval to use turquoise lights on its Level 3 Drive Pilot models, although the company has since shifted its strategy toward a Level 2++ system. The NHTSA’s new proposal seeks to create a uniform national standard that major players in the industry, including Waymo, Nuro, Zoox, GM, and Mercedes, can adopt. This consistency is intended to help the public and law enforcement recognize autonomous technology regardless of the manufacturer.

Under the proposed rule, the installation of cyan marker lamps would remain optional for automakers. However, the agency is setting strict guidelines regarding the color, brightness, and physical placement of these lights. This ensures that if a manufacturer chooses to include them, the setup will be legally compliant and consistent with other vehicles on the road. The goal is to prevent a fragmented landscape where different companies use varying colors or signal patterns, which could lead to confusion for human drivers trying to interpret the vehicle's status.

In addition to adding new lighting requirements, the proposal seeks to remove several existing rules that do not make sense for vehicles without human occupants. Current regulations mandate the presence of physical hazard switches, manual beam shifters, and turn levers inside the cabin. NHTSA is proposing to eliminate these requirements, recognizing that many autonomous vehicles will not have these traditional controls. The agency is also updating the 12.8-volt testing standard to allow automakers to design around modern LED architectures without facing unnecessary administrative hurdles.

The agency is also considering removing requirements that dictate the specific vertical positioning of high-beam and low-beam lights. These updates are part of a wider administrative push by the Department of Transportation to streamline the deployment of autonomous vehicles. By simplifying the regulatory framework, the government hopes to make it easier for automakers to build cars that may lack traditional driver controls, such as steering wheels and pedals, which are primarily designed for human operation.

Despite these efforts to modernize regulations, regulators are still actively enforcing current rules where they apply. Last month, NHTSA initiated an audit query into the Tesla Cybercab. The agency is examining the technical data and processes Tesla relied upon when certifying the vehicle. The primary issue at hand is the Cybercab’s lack of certain design features, including sideview mirrors, pedals, and a steering wheel, all of which are currently required under existing FMVSS standards.

The next steps in this process will involve public comment and finalization of the rule changes. For now, the proposal signals a significant shift in how federal regulators view the interface between autonomous technology and human-driven traffic. By standardizing the visual language of driverless cars, the NHTSA aims to create a safer and more predictable environment as robotaxis become a more common sight on California roads and beyond.