Federal Authorities Propose Cyan Lights for Robotaxis to Indicate They’re in Motion

After years of discussions on how autonomous vehicles should signal their lack of a human driver—whether through flashing text, audio cues, or unique lighting—the government has made a decisive move: introducing cyan as the standard color.

The National Highway Traffic Safety Administration (NHTSA) has proposed updates to the Federal Motor Vehicle Safety Standard (FMVSS) No. 108, specifically tailored for self-driving cars. This initiative aims to cut through the bureaucratic red tape for vehicles without human operators while establishing a uniform way for robotaxis to communicate with other road users, starting with a distinctive cyan light.

NHTSA suggests using cyan-colored marker lamps to “clearly and consistently signal to law enforcement and other road users when an automated driving system is operating the vehicle.” The choice of cyan is strategic; the automotive industry already employs red, amber, white, and flashing blue/red lights for various functions like brakes, turn signals, and emergency alerts. Cyan fills a visual gap without causing confusion among drivers.

There’s also a precedent for this move. Mercedes-Benz received state approval for turquoise lights on its Level 3 Drive Pilot vehicles, although the company has since shifted focus to a Level 2++ system. Nonetheless, NHTSA aims to establish a national standard that can be uniformly adopted by robotaxi operators and automakers alike.

Under the proposed regulations, the use of cyan marker lights would be optional for manufacturers. However, by defining official standards for their color, brightness, and placement, NHTSA seeks to ensure that any automaker opting to implement these lights does so in a consistent and legal manner, avoiding a chaotic mix of colors and signals.

Additionally, NHTSA plans to eliminate certain lighting requirements that are irrelevant for vehicles without human drivers. Current regulations mandate physical hazard switches, manual beam shifters, and turn levers, which would not be necessary in an autonomous setup. The agency is also updating the 12.8-volt testing standard to facilitate the integration of modern LED technologies without excessive regulatory hurdles. Furthermore, NHTSA is considering removing rules that dictate the positioning of high-beam lights in relation to low-beam lights.

This update is part of a larger initiative by the Department of Transportation to simplify the deployment of autonomous vehicles. The goal is to enable manufacturers to create cars that lack traditional controls, such as steering wheels and pedals, which are designed for human operation.

However, regulators are still enforcing existing rules. Recently, NHTSA launched an audit into the Tesla Cybercab to scrutinize the processes and technical data Tesla used for certifying the vehicle, particularly regarding the absence of required design features like sideview mirrors, pedals, and a steering wheel—all mandated under FMVSS.