Federal Agencies Mandate Cyan Lights for Self-Driving Cars

Federal regulators have proposed that driverless vehicles display a specific cyan-colored light to signal they are in autonomous mode. This move aims to end years of industry debate over how robotaxis should visually communicate their status to the world. The National Highway Traffic Safety Administration (NHTSA) released these changes as part of an update to Federal Motor Vehicle Safety Standard No. 108. The goal is to create a consistent visual language for automated driving systems.

The chosen color is cyan, a distinct blue-green hue. NHTSA selected this shade because existing vehicle lighting uses red, amber, white, and flashing blue or red lights for brakes, turns, and emergencies. A cyan light would fill a visual gap without confusing other road users. The agency wants this light to clearly indicate to law enforcement and other drivers that a human is not at the wheel.

There is some historical precedent for this approach. Mercedes-Benz previously received state-level approval for turquoise lights on its Level 3 Drive Pilot vehicles. Although the automaker later dropped that specific system in favor of a different configuration, the concept remains relevant. NHTSA wants to establish a national standard that operators like Waymo, Nuro, and Zoox, as well as manufacturers like GM and Mercedes, can adopt uniformly.

Under the new proposal, cyan marker lights would be optional for manufacturers. However, if a company chooses to include them, the federal rules would dictate the exact color, brightness, and placement. This ensures that any automaker using the feature follows a consistent legal setup. It prevents a confusing mix of different colors and signals from appearing on the road.

The proposal also simplifies existing lighting requirements for vehicles without human drivers. Current rules require physical hazard switches, manual beam shifters, and turn levers inside the car. NHTSA proposes removing these mandates since they are unnecessary for autonomous operation. The agency is also updating the 12.8-volt testing standard to accommodate modern LED architectures. Additionally, it is considering eliminating rules that dictate whether high-beam lights must sit above or below low-beam lights.

This regulatory shift is part of a broader effort by the Department of Transportation to streamline the deployment of autonomous vehicles. The government aims to make it easier for automakers to build cars without traditional controls like steering wheels and pedals. These components are designed for human operators and often complicate the design of driverless vehicles.

Despite these efforts to streamline rules, regulators continue to enforce existing standards strictly. Last month, NHTSA opened an audit query into the Tesla Cybercab. The investigation examines the process and technical data Tesla relied on when certifying the vehicle. The primary issue is the absence of design features such as sideview mirrors, pedals, and a steering wheel, which are currently required under FMVSS. This highlights the tension between modernizing regulations and enforcing current safety codes.