NHTSA Proposes Cyan Marker Lights for Autonomous Vehicles

The long-standing debate over how to visually identify driverless vehicles on the road has finally received a concrete federal answer: cyan.

The National Highway Traffic Safety Administration has released proposed amendments to Federal Motor Vehicle Safety Standard No. 108, specifically targeting the communication protocols for autonomous vehicles. The agency aims to establish a uniform method for robotaxis to signal to law enforcement and other road users that an automated driving system is in control. By mandating a distinct blue-green marker lamp, regulators hope to eliminate the current patchwork of custom lights, flashing text, and audio alerts that have characterized the industry in recent years.

The choice of cyan is driven by the need to fill a visual gap in the automotive color spectrum. Industry standards already reserve red, amber, white, and flashing blue or red lights for critical functions such as braking, turn signals, headlights, and emergency vehicles. NHTSA argues that cyan can occupy this remaining space without causing confusion among human drivers. There is some precedent for this approach, as Mercedes-Benz previously received state-level approval for turquoise lights on its Level 3 Drive Pilot vehicles, although the automaker later abandoned that specific design in favor of a Level 2++ system.

Under the new proposal, the installation of cyan marker lights would remain optional for manufacturers. However, the agency intends to set strict federal standards regarding their color, brightness, and placement. This framework ensures that any automaker opting to use these lights does so with a consistent, legally defined setup rather than an arbitrary mix of hues. The goal is to create a recognizable national standard that operators like Waymo, Nuro, and Zoox, as well as manufacturers including GM and Mercedes, can adopt uniformly.

Beyond adding new lighting requirements, the proposal seeks to remove outdated regulations that no longer apply to vehicles without human drivers. Current rules mandate the presence of physical hazard switches, manual beam shifters, and turn levers inside the cabin. NHTSA proposes eliminating these requirements, recognizing that they are unnecessary for fully automated systems. The agency is also updating the 12.8-volt testing standard to accommodate modern LED architectures, reducing administrative hurdles for engineers.

Additionally, NHTSA is considering removing the rule that dictates the vertical positioning of high-beam lights relative to low-beam lights. This change is part of a broader Department of Transportation initiative to streamline the deployment of autonomous vehicles. The administration is working to make it easier for automakers to design cars that lack traditional human-centric controls, such as steering wheels and pedals, which are standard in current FMVSS requirements.

This regulatory update arrives at a pivotal moment for the sector, balancing the desire for simplified designs with the need for rigorous oversight. While the agency is moving to reduce red tape for human-free designs, it is simultaneously enforcing existing rules strictly. Last month, NHTSA initiated an audit query into the Tesla Cybercab to examine the technical data and processes Tesla used to certify the vehicle. The investigation focuses on the absence of design features like sideview mirrors, pedals, and steering wheels, all of which are currently required under federal standards.

As the proposal moves forward, the industry will watch closely to see how these changes impact vehicle design and market entry. The shift toward standardized cyan lighting and the removal of legacy interior controls could accelerate the rollout of driverless services, provided the regulatory framework continues to balance innovation with safety.