New Federal Proposal Would Standardize Cyan Lights on Autonomous Vehicles

A specific shade of blue-green light could soon become the universal sign that no human is driving a car.

The National Highway Traffic Safety Administration has proposed modifying Federal Motor Vehicle Safety Standard No. 108 to accommodate the realities of autonomous vehicles. The agency is putting forward a set of changes designed to both streamline the manufacturing of driverless cars and establish a uniform method for these vehicles to signal their status to the public. The core of this proposal is the establishment of a new federal standard for a specific kind of light.

The central element of the proposed rulemaking involves the use of cyan-colored marker lamps. According to the agency, such lights are intended to clearly and consistently signal to law enforcement and other road users when an automated driving system is operating the vehicle. The choice of this particular color is a deliberate one, aiming to find a visual space unoccupied by existing automotive lighting conventions. Red, amber, and white are already assigned to critical functions like brakes, turn signals, and headlights, while blue and red are reserved for emergency vehicles.

This is not the first time such a color has been considered for this purpose. Mercedes-Benz previously received state-level approval to equip its Level 3 Drive Pilot vehicles with turquoise lights, an initiative the automaker has since abandoned in favor of a different system. Despite this, federal regulators are moving to create a national standard. This would provide a uniform specification for a wide range of companies developing autonomous technology, including Waymo, Nuro, and Zoox, as well as automakers like GM and Mercedes.

It is important to note that under this proposal, the installation of these lights would be optional for manufacturers. However, by creating an official federal standard that defines their color, brightness, and location, the agency wants to ensure that any automaker who chooses to add them uses a consistent and legally compliant setup instead of a confusing mix of different colors and signals.

The proposed rule also includes changes that would eliminate certain lighting requirements that are irrelevant to a vehicle without a human driver. Current regulations demand physical hazard switches, manual beam shifters, and turn levers inside vehicles, features that serve no purpose in a car without a human to operate them. The agency is also proposing to remove these requirements, while also updating the 12.8-volt testing standard so automakers can build around modern LED architectures without jumping through administrative hoops. And NHTSA is considering getting rid of requirements dictating whether high-beam lights sit above or below low-beam lights.

This update is part of a broader push to streamline the deployment of autonomous vehicles. The government wants to make it easier for automakers to build cars without traditional controls like steering wheels and pedals, which are designed for vehicles operated by human drivers. Federal regulators are also still enforcing the rules as they’re written. Last month, NHTSA opened an audit query into the Tesla Cybercab to examine the process and technical data on which Tesla relied when certifying the Cybercab and related issues. At issue is the absence of certain design features such as sideview mirrors, pedals, and steering wheel, all of which are required under FMVSS.