Automotive Lighting: Feds Propose Cyan Signal for Driverless Cars

The color cyan is about to become the most important hue on the American road, at least for a specific slice of the automotive market. Federal regulators are proposing that driverless vehicles use a distinct blue-green light to signal to the world that no human is behind the wheel. This specific shade has been selected to fill a visual gap in traffic communication, offering a clear indicator that an automated driving system is in control.

The National Highway Traffic Safety Administration (NHTSA) released these proposed changes to Federal Motor Vehicle Safety Standard No. 108. The goal is to rewrite rules that were originally designed for human-driven cars to better fit autonomous vehicles. The agency wants to cut red tape for designs that do not include traditional controls while simultaneously standardizing how these robotaxis communicate with other road users and law enforcement. The core of this proposal is the introduction of cyan-colored marker lamps.

The choice of cyan is not arbitrary. The auto industry already relies on a specific palette of colors for various functions. Red and amber are used for brakes and turn signals, white for headlights, and flashing blue or red lights for emergency vehicles. By introducing cyan, regulators hope to create a signal that is visually distinct from all existing automotive lighting, reducing the chance of confusion among drivers and police officers who need to identify an autonomous vehicle quickly.

There is some precedent for this type of signaling, though it has not been widespread. Mercedes-Benz received state-level approval to use turquoise lights on its Level 3 Drive Pilot vehicles. However, the automaker has since moved away from that specific Level 3 approach in favor of a Level 2++ system. Despite this shift, NHTSA is looking to establish a national standard that operators like Waymo, Nuro, and Zoox, as well as major automakers including GM and Mercedes, can adopt uniformly across the country.

Under the current proposal, the installation of these cyan marker lights would remain optional for manufacturers. However, the agency intends to set official federal standards regarding the color, brightness, and location of the lights. This ensures that if a carmaker chooses to include them, the setup is consistent and legally compliant, rather than part of a confusing mix of different colors and signals that might vary by brand.

The rule change also involves removing lighting requirements that do not make sense for vehicles without a human driver. Current regulations demand the presence of physical hazard switches, manual beam shifters, and turn levers. NHTSA is proposing to remove these mandates, allowing for cleaner interior designs. Additionally, the agency is updating the 12.8-volt testing standard to accommodate modern LED architectures, which should reduce administrative hurdles for manufacturers building these new systems.

NHTSA is also considering eliminating rules that dictate the vertical placement of high-beam lights relative to low-beam lights. This part of the update is part of a broader push 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, such as steering wheels and pedals, which are traditionally required for human-operated vehicles.

Despite these moves to modernize regulations, regulators are still enforcing existing rules strictly. Last month, NHTSA opened an audit query into the Tesla Cybercab. The agency is examining the technical data and processes Tesla used to certify the vehicle, particularly focusing on the absence of design features like sideview mirrors, pedals, and a steering wheel. These features are currently required under FMVSS, highlighting the ongoing tension between new autonomous designs and established safety standards.