A new road colour could soon signal that no one is driving — but the lights would be optional, and the rule is not final.
October 24, 2026 — The U.S. National Highway Traffic Safety Administration (NHTSA) has proposed letting driverless vehicles carry optional cyan marker lamps that glow only while an automated driving system (ADS) is in control and no occupant is expected to watch the road. The proposal, filed on October 23, 2026, would also rewrite parts of the federal lighting standard for cars built without a steering wheel or pedals.
Image: A driverless robotaxi with glowing cyan marker lights at night. Credit: AI-generated illustration / Red Eye Eagle News.
Editor's Highlight: The idea is simple — one colour for "nobody is driving" — but the proposal does not require it, so its value depends on how many operators fit the lamps.
Table of Contents
- What NHTSA Actually Proposed
- Why Cyan, and Why Now
- How the Marker Lamps Would Work
- The Other Rule Changes for Cars Without Controls
- What This Means for Robotaxis and Pedestrians
- What Happens Next
- Bottom Line
- FAQ
- Sources
Key Facts
| Detail | Information |
|---|---|
| Agency | National Highway Traffic Safety Administration (NHTSA) |
| Proposal | Modernization of FMVSS No. 108 to Accommodate ADS-Equipped Vehicles |
| Docket | NHTSA-2026-1519 |
| Filed | October 23, 2026 |
| Federal Register publication | Scheduled for October 26, 2026 |
| Comment period | 30 days after publication, around November 25, 2026 |
| Marker lamps | Optional cyan ADS lamps, steady-burning, 4 to 8 per vehicle |
| Status | Proposal only, not a final rule |
What NHTSA Actually Proposed
The filing is a notice of proposed rulemaking covering Federal Motor Vehicle Safety Standard (FMVSS) No. 108, which governs lamps, reflectors and lighting controls on U.S. vehicles. It is titled "Modernization of FMVSS No. 108 to Accommodate ADS-Equipped Vehicles" (docket NHTSA-2026-1519).
The Federal Register entry, document 2026-21794, is scheduled for formal publication on October 26, 2026. From that date, the agency is asking for comments within 30 days, putting the deadline around November 25, 2026.
Why Cyan, and Why Now
Today, a pedestrian or police officer looking at a car has no standard way to tell whether a person or software is in charge — a real problem at crosswalks and traffic stops.
NHTSA says it worries that "differing and contradictory" company lights could confuse road users, and that one national specification would give everyone a single colour to learn.
How the Marker Lamps Would Work
The rule is an "if equipped" standard: NHTSA says it lacks enough information to require a lamp on every automated vehicle, so none would be forced to fit one — but any fitted lamp must meet the specification.
The trigger is the situation on the road, not a marketing label: the lamp indicates operation "without the expectation that an occupant is monitoring the roadway." A driverless robotaxi qualifies; a supervised assistance system, where the driver must watch the road, does not.
The colour is cyan, the blue-green shade defined in SAE J578. NHTSA rejected amber, red or white, which already mean turn signals, brakes and headlamps, while flashing blue and red belong to emergency vehicles. The specs largely follow SAE J3134, revised in December 2025.
| Feature | Proposed specification |
|---|---|
| Colour | Cyan, as defined in SAE J578 |
| Number | 4 to 8 lamps in total |
| Placement | 1 or 2 on the front, each side and the rear |
| Mounting height | At least 15 inches above the ground |
| Behaviour | Steady-burning, not flashing |
| Combination | Must not be optically combined with another lamp |
Tech Analysis: The strongest case for a marker lamp is social, not technical: driverless cars share streets with people who cannot see software, so they need a legible signal.
The Other Rule Changes for Cars Without Controls
For the industry, the control changes may matter even more than the lamps: a robotaxi has no steering wheel to cancel a turn signal and no stalk to flick between beams, yet current text assumes a human operates them.
Under the proposal, manual control requirements for turn signals, hazard lights, beam switching and related dashboard telltales would apply only to vehicles with manually operated controls. Driverless vehicles would still need those functions, controlled by the automated system.
Practical Takeaway: The proposal does not remove safety functions — only the assumption that a human hand or foot must operate them.
What This Means for Robotaxis and Pedestrians
Some coverage has linked the timing to designs such as Tesla's Cybercab, with no steering wheel or pedals. The filing itself, however, does not name any manufacturer's product as the reason for the change.
What the filing does credit is Mercedes-Benz, which presented marker-lamp recommendations and ran a two-year validation with five vehicles in California from 2023 to 2025.
On state law, NHTSA's tentative view is that state limits on light colours would be pre-empted only where they block a compliant ADS marker lamp.
What Happens Next
The next step is public comment, due 30 days after publication on October 26, 2026. Comments could change the colour, brightness, the ban on optical combination, or whether lamps may flash.
Timing after that is open. A safety standard normally takes effect 180 days after issue, but the filing argues for immediate effect because the changes add flexibility rather than burden.
Bottom Line
NHTSA has proposed a clear idea: an optional cyan lamp saying, without words, that no occupant is expected to watch the road, plus updates that stop pretending every car has a steering wheel. It is still only a proposal — watch the comment deadline around November 25, 2026.
FAQ
Will every self-driving car have to show cyan lights?
No. The lamps would be optional, but any fitted lamp must meet the federal specifications for colour, brightness, placement and activation.
When would the cyan lights turn on?
Only while the vehicle operates without the expectation that an occupant is monitoring the roadway, such as a driverless robotaxi mode. The lamps burn steadily, then switch off.
Could a car using supervised driver assistance use the lights?
Based on the draft wording, no. Supervised systems expect the driver to watch the road and take over, so they do not meet the definition.
Why did NHTSA pick cyan instead of another colour?
White, amber, red and flashing blue/red already mean headlamps, turn signals, brakes and emergency vehicles. Cyan, as defined in SAE J578, has no existing meaning on U.S. roads.
Is this rule final, and when could it take effect?
It is not final. It is scheduled for publication on October 26, 2026, with a 30-day comment period. A standard normally takes effect 180 days after issue, although the filing argues for immediate effect.
Sources
- SaveDelete — NHTSA Cyan Robotaxi Lights: What the Proposal Changes
- EVwire — NHTSA proposes lighting rule changes for driverless vehicles without steering wheels, adds optional cyan ADS lamps
- WebProNews — NHTSA Wants Robotaxis to Display a Color to Indicate They Are In Driverless Mode
- YouTube, Mustard Explains — Tesla's Car With No Steering Wheel Is Already Picking Up Passengers
- Bloomberg Law — Green-Blue Lights on the Road Could Soon Mean a Driverless Car
- Image source: AI-generated illustration / Red Eye Eagle News (hero image for this article).
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