Why It Matters
Vehicle makers without manually operated driving controls would gain design flexibility under a National Highway Traffic Safety Administration proposal that would also allow cyan automated driving system (ADS) marker lamps as optional lighting equipment in ADS-equipped vehicles.
NHTSA says it cannot quantify the number of vehicles affected "given the still-developing nature of this market," but describes the action as an Executive Order 14192 deregulatory measure intended to "remove unnecessary requirements and to provide design flexibility without impact on vehicle safety." The proposal is part of a broader NHTSA effort that began with a 2018 request for comment and a 2019 advance notice of proposed rulemaking. Earlier notices proposed similar changes to other Federal Motor Vehicle Safety Standards.
The Big Picture
The proposal's changes fall into four clusters. For vehicles without manually operated driving controls, the rule would remove requirements that the turn signal operating unit be self-canceling by steering wheel rotation and cancelable by a manually operated control. It would also remove the requirement that the headlamp beam switching device be operable by a driver's hand or foot. Turn signal telltales and upper beam headlamp telltales would be required only on vehicles with manually operated driving controls. Vehicles without turn signal telltales would instead need a lamp failure telltale "displayed in clear view of all designated seating positions."
The proposal adds a new optional standard for cyan-colored automated driving system marker lamps. Federal Motor Vehicle Safety Standard (FMVSS) No. 108 currently has "no specific requirements for a lamp with the purpose of communicating to other road users that a vehicle is operating without the expectation that an occupant is monitoring the roadway." The new provisions would establish those requirements for the first time. If a manufacturer chooses to install the lamps:
- Lamps must be steady-burning and cyan in color, consistent with the applicable color specifications in SAE Standard J578.
- Between four and eight ADS marker lamps would be permitted, as specified in Table I-a.
- No ADS marker lamp could be optically combined with another lamp or reflective device.
NHTSA says standardization "will mitigate the risk of manufacturers implementing non-standardized lamp applications, which may become a nuisance, cause confusion, or otherwise have potential negative safety outcomes."
The proposal would also remove a requirement in place since 1989 that, in a vertical headlamp arrangement, the lower beam be placed above the upper beam, allowing manufacturers to place the lower beam below the upper beam. For integral beam headlamps only, it would replace the existing 12.8-volt direct-current test standard with testing at the voltage marked on the lamp by the manufacturer, plus or minus 20 millivolts. Other headlamp types would retain the existing test voltage requirement.
Today, 49 C.F.R. § 571.108 defines the vehicular hazard warning signal operating unit as "a driver-controlled device which causes all required turn signal lamps to flash simultaneously to indicate to approaching drivers the presence of a vehicular hazard." The proposed text replaces that language with "an operating unit by which the operator of a vehicle," removing the implication that a human driver must control the device. Currently, S6.6.1 generally requires vehicles other than trailers to carry a turn signal telltale and upper beam headlamp telltale. The proposed revision would apply those telltale requirements only to vehicles with manually operated driving controls, while retaining the hazard warning signal telltale requirement.
NHTSA Administrator Jonathan Morrison described the changes as addressing "unnecessary regulatory burdens" while establishing performance standards for marker lamps. NHTSA does not anticipate incremental costs from the test voltage change, vertical headlamp arrangement change, modifications for ADS vehicles without manual controls or optional ADS marker lamps. It also says it "does not anticipate any safety disbenefits for the proposed changes."
California law explicitly permits ADS marker lamps under provisions in effect as of January 2026. NHTSA tentatively concludes that the federal proposal, if finalized, would partially preempt California's provisions where the federal requirements differ from SAE J3134.
If finalized, NHTSA intends to make the rule effective immediately upon publication, arguing that the changes increase manufacturer flexibility and require no compliance lead time. Federal law generally bars a new FMVSS from taking effect before 180 days after issuance unless NHTSA finds good cause for a different effective date.
The Bottom Line
Comments are due Nov. 25 under Docket No. NHTSA-2026-1519. The Federal Register currently lists 40 comments received. Comments may be submitted at regulations.gov, by fax to 202-493-2251, or by mail to Docket Management, U.S. Department of Transportation, 1200 New Jersey Avenue SE, West Building, Suite W58-213, Washington, DC 20590.
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