Self-driving vehicles could use steady cyan lamps to show that no human is expected to be watching the road, under a federal proposal that would write the first specifications for such lights into the national vehicle lighting standard. The National Highway Traffic Safety Administration released the proposed rule on Friday ahead of its formal publication in Monday's Federal Register. The same proposal would free vehicles built without steering wheels or pedals from lighting controls designed around a human driver.
The lamps would be optional. A vehicle equipped with them would carry one or two on each of the front, sides and rear, from four to eight in all, mounted at least 15 inches off the ground, according to the notice. They would burn steadily, switch on and off together and come on automatically only while the vehicle operates without the expectation that an occupant is monitoring the road. When a person is expected to take up that job again, the lamps would have to shut off. Vehicles without automated driving capability could not carry them. The agency asked whether the lamps should also be allowed to flash.
NHTSA said the lamps are meant "to clearly and consistently signal to law enforcement and other road users when an automated driving system is operating the vehicle," The Verge reported. Red, amber and white already mark brakes, turn signals and headlights, and emergency vehicles flash red and blue; cyan could fill the gap without confusing other drivers, the publication noted. The agency is not proposing to require the lamps on every automated vehicle, and it said it cannot yet estimate their safety benefits or say how many vehicles the proposal would reach in a market that is still taking shape.
The proposed color is the blue-green defined by SAE International, and the specifications follow most, though not all, of the engineering group's consensus standard for these lamps, the notice says. It credits Mercedes-Benz with a two-year road trial of the lamps in California from 2023 to 2025 using five vehicles, and it notes that California law already permits them on automated vehicles. The notice also points to work on such lamps by a United Nations vehicle-regulation group and in China, and to a recommendation from the American Association of Motor Vehicle Administrators that the lamps be used to help police tell whether a vehicle is being driven by its automated system or by a person. China released a similar optional draft standard the same week, using turquoise, that would take effect in 2028, Electrek reported.
The rest of the proposal is aimed at vehicles with no manual driving controls at all. Such vehicles are not sold to consumers, but some manufacturers and ride-hailing operators have deployed them in a number of cities and others are testing them around the country, the agency wrote. The current standard still requires manually operated turn signal, hazard warning and beam switching controls, and NHTSA would limit those requirements, along with certain dashboard indicator rules, to vehicles that have manual driving controls. Cars that keep a steering wheel and pedals would see no change in those requirements. Among the rules that would no longer apply to the others is the requirement that a turn signal cancel itself after the steering wheel turns past a set point and straightens out, which means little in a car with no wheel, Electrek noted.
NHTSA said it is working "to remove unnecessary barriers to technological innovation while ensuring motor vehicle safety is not compromised." Without the change, the agency expects that builders of such vehicles would seek exemptions from the standard rather than install equipment it considers unnecessary. It also argued that taking lamp controls away from passengers could improve safety by keeping an occupant from interfering with the lamps in ways that could cause problems for other road users, and it said it anticipates no added costs and no loss of safety from the changes.
Two smaller changes would reach conventional cars as well. Integral beam headlamps, which NHTSA says the market has moved to, would no longer have to be tested at a fixed 12.8 volts, a standard that once ensured ready replacements for incandescent and halogen bulbs that did not last the life of a car. Replaceable bulb and sealed beam headlamps would still be tested at that voltage. The agency would also drop the rule that the uppermost lamp must supply the low beam when headlamps are stacked vertically, while leaving minimum and maximum mounting heights alone.
The Office of Management and Budget reviewed the proposal as a significant regulatory action, and NHTSA expects it to count as deregulatory under the administration's executive order on cutting regulation if it is finalized as written. The agency has not quantified the benefits or costs. Because every change adds flexibility rather than new obligations, it said manufacturers would need no lead time and a final rule should take effect as soon as it is adopted. Administrator Jonathan Morrison signed the notice, and comments are due Nov. 25.
The proposal fits a broader Transportation Department push to make it easier to build vehicles without steering wheels and pedals, The Verge reported, though regulators are still enforcing the rules now on the books. Last month NHTSA opened an audit query into Tesla's Cybercab to examine the process and technical data Tesla relied on in certifying the vehicle, a review centered on its lack of features such as side mirrors, pedals and a steering wheel that current standards require. Electrek's commentary called the lighting proposal "a long time coming" and needed, while warning that the loosening of rules for autonomous vehicles deserves close attention.