Changes would allow special identification lights and eliminate unnecessary manual controls
What if you could tell whether a truck traveling alongside you on the interstate was being operated by a human driver or an automated driving system — simply by looking at its lights?
That could become a reality under a new proposal from the National Highway Traffic Safety Administration (NHTSA).
In a notice of proposed rulemaking published in the Federal Register Oct. 26, NHTSA outlines several proposed changes to federal vehicle lighting standards, including allowing special cyan-colored lights to identify vehicles operating under automated driving systems (ADS).
The proposal would also eliminate certain requirements for manually operated lighting controls in vehicles designed to operate without human drivers.
The proposed changes would update Federal Motor Vehicle Safety Standard (FMVSS) No. 108, which governs lamps, reflective devices and associated equipment on motor vehicles, including commercial trucks.
A new signal for autonomous operation
Perhaps the most visible change would be the addition of optional cyan-colored marker lights that would signal when a vehicle is being operated by an automated driving system rather than a human driver. Unlike traditional blue emergency lights, the proposed ADS marker lights would emit a steady blue-green glow.
Under the proposal, vehicles equipped with cyan-colored marker lights would have between four and eight lights, with one or two positioned on the front, rear and each side. The lights would be mounted at least 15 inches above the roadway.
The lights could activate automatically during autonomous operation but would be required to turn off when a human occupant is expected to monitor the roadway. The lights would NOT be mandatory. Instead, NHTSA would establish consistent requirements for manufacturers that choose to install them.
According to NHTSA, using a consistent lighting system could help motorists, pedestrians and law enforcement officers recognize vehicles operating autonomously while avoiding confusion caused by different lighting designs.
The proposal follows the development of industry standards for ADS marker lights, including SAE International’s J3134 standard.
NHTSA also points to an international survey of more than 4,400 drivers in four countries. More than 80% of respondents in the United States and United Kingdom indicated that ADS-equipped vehicles should have marker lights identifying their automated operation.
Adapting lighting controls for driverless vehicles
Another portion of the proposal addresses vehicles designed to operate without traditional driving controls, such as steering wheels, accelerator pedals or brake pedals.
Current federal lighting regulations specify how human drivers must operate certain equipment, including turn signals, hazard warning lights and headlamp beam switches. Those requirements can create design challenges for vehicles that have no human driver. Under the proposal, certain specifications for manually operated controls would apply only to vehicles equipped with traditional driving controls.
However, NHTSA is not proposing to eliminate the lighting functions themselves.
Driverless vehicles would still be required to have functioning turn signals and the ability to switch between high- and low-beam headlights, but those functions could be controlled electronically rather than through switches designed for human use.
The proposal would also revise requirements for dashboard indicators, sometimes called telltales, that alert drivers when certain lighting equipment is operating.
Vehicles equipped with manual driving controls would continue to be subject to existing requirements, even if they also have automated driving capabilities.
Updating requirements for modern headlights
The proposed rule also addresses two longstanding headlamp requirements that NHTSA says may no longer be necessary because of advancements in lighting technology.
One change would revise testing requirements for integral-beam headlights, which incorporate their light sources into the headlamp assembly. Rather than requiring these lights to be tested at a standardized voltage of 12.8 volts, NHTSA proposes testing them at the voltage specified by the manufacturer.
A second change would eliminate a requirement that low-beam headlights be positioned above high-beam headlights when the two are arranged vertically. According to NHTSA, improvements in headlamp technology have made that requirement unnecessary. Minimum and maximum headlamp mounting heights would remain unchanged.
State lighting laws raise questions
The proposed cyan marker lights could also raise questions about state laws governing vehicle lighting colors. Many states restrict the use of blue lights, particularly those associated with law enforcement and emergency vehicles.
NHTSA maintains that the proposed cyan lights would be distinguishable from emergency lighting because of their color, lower intensity and steady illumination.
The agency is requesting public input on how the proposed standards would interact with existing state laws and whether federal regulations would override certain state restrictions.
Public comments accepted through Nov. 25
The proposed changes are part of NHTSA’s ongoing effort to update federal motor vehicle safety standards to accommodate automated driving technology while maintaining existing vehicle safety protections.
The proposal does not require manufacturers to install ADS marker lights, authorize autonomous vehicle operations or eliminate existing lighting requirements for vehicles with traditional driving controls.
NHTSA is accepting public comments through Nov. 25, 2026. Comments may be submitted through Regulations.gov under docket number NHTSA-2026-1519.
Linda Garner-Bunch has been with The Trucker since 2020, picking up the reins as managing editor in 2022. Linda has nearly 40 years of experience in the publishing industry, covering topics from the trucking and automotive industry to employment, real estate, home decor, crafts, cooking, weddings, high school sports — you name it, she’s written about it. She is also an experienced photographer, designer and copy editor who has a heartfelt love for the trucking industry, from the driver’s seat to the C-suite.
