Automated Driving: The Federal Case for Cyan

The federal government has identified a single specific color as the solution to a multi-year debate: cyan. After years of industry speculation regarding how driverless vehicles should visually distinguish themselves from human-operated cars, the National Highway Traffic Safety Administration (NHTSA) has proposed a standardized blue-green light for autonomous systems. This move aims to replace a fragmented landscape of potential signaling methods with one uniform federal standard.

The proposal rewrites Federal Motor Vehicle Safety Standard (FMVSS) No. 108 to accommodate the unique requirements of autonomous vehicles. The agency argues that a distinct cyan marker lamp would provide a clear and consistent signal to law enforcement and other road users that an automated driving system is in control. By selecting this specific hue, regulators are attempting to fill a visual gap in the current automotive lighting spectrum, which is already heavily occupied by red, amber, white, and flashing blue or red lights used for braking, signaling, and emergency purposes.

While the proposal is not yet law, it establishes a framework for how these lights should function if manufacturers choose to implement them. The rules would dictate the color, brightness, and location of the cyan lamps to ensure consistency across the industry. This standardization is intended to prevent a confusing patchwork of different colors and signals from different automakers, allowing operators like Waymo, Nuro, and Zoox, as well as manufacturers like GM and Mercedes, to adopt a uniform approach.

There is some precedent for this specific color choice. Mercedes-Benz previously received state-level approval for turquoise lights on its Level 3 Drive Pilot vehicles. However, the automaker has since abandoned that specific hardware in favor of a Level 2++ system. Despite this industry shift, NHTSA is moving forward with a national standard to ensure that if cyan lights are used, they are legally consistent and easily recognizable.

Beyond adding new requirements, the proposal seeks to remove legacy rules that are impractical for vehicles without human drivers. Current regulations mandate physical components such as hazard switches, manual beam shifters, and turn levers, which are redundant in an automated system. NHTSA proposes eliminating these mandates to reduce administrative burdens and allow for more streamlined vehicle designs.

The agency is also updating technical standards to reflect modern engineering. This includes revising the 12.8-volt testing standard to accommodate LED architectures without excessive bureaucratic hurdles. Additionally, NHTSA is considering removing requirements that dictate the physical placement of high-beam lights relative to low-beam lights, further streamlining the design process for autonomous platforms.

This regulatory update is part of a broader Department of Transportation push to simplify the deployment of autonomous vehicles. The goal is to make it easier for automakers to build cars that lack traditional human controls, such as steering wheels and pedals. By standardizing the external signals and removing internal physical requirements, the federal government aims to lower the barriers to entry for fully driverless designs.

However, the path to full autonomy remains complex. While NHTSA is proposing to relax certain rules for future vehicles, it is still strictly enforcing existing regulations for current models. Last month, the agency opened an audit query into the Tesla Cybercab to examine the technical data Tesla relied on for certification. The investigation focuses on the absence of traditional features like sideview mirrors, pedals, and steering wheels, which are currently required under FMVSS. This dual approach highlights the tension between encouraging new design standards and maintaining rigorous oversight of existing certifications.