Federal Agencies Propose Mandatory Cyan Lights for Driverless Vehicles

The debate over how self-driving cars should communicate their status has lasted for years, but federal regulators have finally offered a specific solution. The National Highway Traffic Safety Administration (NHTSA) has released proposed changes to Federal Motor Vehicle Safety Standard No. 108. The core of this proposal involves requiring a distinct blue-green light to signal that an automated system is in control.

The agency argues that cyan is the logical choice for this new visual cue. Current automotive lighting standards already reserve red, amber, white, and flashing blue or red lights for specific functions like braking, turning, and emergency alerts. By introducing cyan, regulators aim to fill a visual gap without confusing other drivers or law enforcement. This standard would create a uniform signal for robotaxi operators such as Waymo, Nuro, and Zoox, as well as major automakers including GM and Mercedes-Benz.

There is already some precedent for this type of lighting. Mercedes-Benz previously received state-level approval to use turquoise lights on its Level 3 Drive Pilot vehicles. Although the company later abandoned that specific plan in favor of a Level 2++ system, the NHTSA views the move as a step toward a national standard. The goal is to ensure that any manufacturer choosing to implement these lights does so with a consistent, legal setup regarding color, brightness, and placement.

While the cyan marker lamps would be optional for manufacturers, the federal standards would dictate exactly how they must be built. This prevents a fragmented market where different companies use different colors or signals. The NHTSA is also proposing to remove several lighting requirements that do not apply to vehicles without human drivers. Specifically, the proposal seeks to eliminate the need for physical hazard switches, manual beam shifters, and internal turn levers. It also updates the 12.8-volt testing standard to accommodate modern LED architectures more easily.

This regulatory update fits into a broader push by the Department of Transportation to streamline the deployment of autonomous vehicles. The government aims to make it simpler for automakers to design cars without traditional controls like steering wheels and pedals. However, the agency is still enforcing existing rules strictly. Last month, the NHTSA opened an audit query into the Tesla Cybercab to examine the technical data Tesla used to certify the vehicle. The focus of that inquiry is the absence of required features such as sideview mirrors, pedals, and a steering wheel under current FMVSS rules.

The proposal is currently open for review as part of the ongoing effort to modernize vehicle safety standards. If finalized, these changes would provide a clear framework for how driverless technology interacts with the rest of the road. For now, the cyan light remains a proposal, but it represents a significant step toward defining the visual language of autonomous driving in the United States.