Autonomous Trucking • ELDT.LIVE
NHTSA Proposes Cyan Marker Lights for Fully Automated Vehicles
A new federal proposal would standardize optional cyan lamps that show when an automated driving system is actively controlling a vehicle, while updating lighting rules for vehicles built without manual controls.
NHTSA opened a new lighting-rule proposal
NHTSA announced on October 23 that it is proposing amendments to Federal Motor Vehicle Safety Standard No. 108, the federal standard for lamps, reflective devices, and associated equipment. The agency signed the notice of proposed rulemaking on October 22 and submitted it for publication in the Federal Register. The proposal applies across vehicle categories covered by FMVSS 108, including trucks and buses, and includes provisions specifically designed for vehicles operated by automated driving systems.
Cyan lamps would identify active automated operation
The proposal would create standardized specifications for optional ADS marker lamps. If a manufacturer equips a vehicle with them, the lamps would use a cyan color and meet federal criteria for number, front, rear and side placement, activation, visibility, and light intensity. Their purpose would be to help law enforcement, pedestrians, and other road users recognize when an automated driving system is in full, active control of the driving task.
The marker lamps would be optional, not mandatory
NHTSA is not proposing to require an ADS marker lamp on every automated vehicle. Instead, the rule would regulate how the lamp must perform when a manufacturer chooses to install it. That distinction matters: the proposal would create a consistent signal rather than promise that every automated truck or passenger vehicle will display cyan lighting.
Vehicles without manual controls are the main design issue
FMVSS 108 was written around human-operated controls such as a turn-signal stalk, hazard switch, and hand- or foot-operated headlamp-beam selector. NHTSA proposes to narrow certain manual-control and telltale requirements so they apply to vehicles that actually have manually operated driving controls. A purpose-built automated vehicle without a steering wheel or service-brake pedal would still need a means to operate its turn signals, hazard warning lamps, and high and low beams, but that means could be controlled by the ADS rather than a person.
Conventional trucks would keep their existing requirements
The proposal says vehicles equipped with manually operated driving controls would continue to meet the existing requirements, even if they also have an automated driving system. It does not remove the normal lighting, signaling, conspicuity, inspection, or maintenance duties for today's driver-operated tractors and straight trucks. A fleet should not interpret the notice as permission to delete controls, change required lamp colors, or install an unapproved identification light.
The proposal also modernizes headlamp testing and layout
Two changes are not limited to automated vehicles. NHTSA proposes allowing integral-beam headlamps to be tested at a manufacturer-specified design voltage instead of the existing fixed 12.8 volts, reflecting newer LED and integrated lighting technology. The agency also proposes removing the rule that dictates which lamp must sit above the other when upper and lower headlamp beams are arranged vertically, while retaining illumination and mounting-height requirements.
What a cyan lamp would mean to a CDL driver
If the proposal becomes final and the lamps enter service, a cyan marker would indicate that an ADS is actively performing the driving task. It would not grant the automated vehicle a special right of way, replace its turn signals or brake lamps, or tell another driver that a lane change is safe. CDL drivers should continue using spacing, mirrors, signal observation, speed control, and defensive-driving judgment around any automated vehicle.
Maintenance teams should wait for a final standard
This is not a retrofit instruction. Fleets should continue maintaining required lamps and reflective material under the rules that are currently in force and follow the vehicle manufacturer's service information for any factory-installed automated-driving indicator. If cyan marker lamps are standardized later, technicians will need model-specific procedures for operation checks, fault reporting, replacement parts, aiming or visibility, and interactions with the rest of the lighting system.
The proposal does not authorize driverless trucking by itself
Changing FMVSS 108 would address how eligible vehicles are built and certified; it would not by itself approve a carrier, route, operating area, cargo, or state-level commercial deployment. Automated-truck operations remain subject to other federal and state requirements, permits, exemptions, vehicle rules, and company safety procedures. The lighting notice is one part of a broader federal effort to modernize standards for vehicles that may not include traditional controls.
A 30-day comment period will follow Federal Register publication
NHTSA says comments will be due 30 days after the notice is published in the Federal Register. The prepublication version does not yet supply the calendar deadline, so stakeholders should use the official publication date rather than guess. Comments and supporting material should reference Docket No. NHTSA-2026-1519. The agency also says this proposal is separate from the negotiated rulemaking announced for other parts of FMVSS 108.
Educational summaries help you prepare, but official FMCSA and state licensing sources remain the authority for current requirements.
Official sources
NHTSA — Vehicle Lighting Standards Proposal for Automated Vehicles ↗NHTSA — Notice of Proposed Rulemaking: Modernization of FMVSS No. 108 ↗Regulations.gov — Docket NHTSA-2026-1519 ↗eCFR — 49 CFR 571.108, Lamps and Reflective Devices ↗ELDT.live independently creates and reviews its content. We do not present practice questions as official examination questions and do not guarantee a licensing result.