NHTSA proposes optional cyan lights for automated vehicles

NHTSA has proposed changes to U.S. Federal Motor Vehicle Safety Standard No. 108 (FMVSS No. 108) that would allow optional cyan lamps to signal when an automated driving system (ADS) operates without an occupant expected to monitor the road. The Federal Register notice is set for publication on Oct. 26, 2026, and sets Nov. 25, 2026, as the deadline for public comments.

What the proposed cyan lamps would signal

The lamps would identify a specific operating state: the vehicle is running under ADS without an expectation that an occupant is watching the roadway. They would be optional for ADS-equipped vehicles covered by FMVSS No. 108, not required on every such vehicle. The proposal applies to vehicle categories under the U.S. standard, rather than to one automaker or model.

NHTSA proposes steady-burning cyan lamps that switch on and off together. They would turn off automatically when an occupant is expected to monitor the road. A vehicle could have four to eight lamps: one or two at the front, one or two on each side, and one or two at the rear. Each would be mounted at least 15 inches above the ground and kept optically separate from other lamps and reflective devices.

The proposed maximum intensity depends on the lamp’s position and whether the headlamps are on. Candela (cd) measures luminous intensity in a direction.

These are proposed regulatory limits, not readings from lamps on vehicles in operation. The lower side-and-rear maximum with headlamps on makes the allowed intensity depend on the surrounding lighting state as well as lamp position.

Which other lighting rules could change

For ADS-equipped vehicles without manually operated driving controls, NHTSA proposes removing certain requirements built around human-operated controls. These include steering-wheel-based turn-signal cancellation rules and hand-or-foot operation requirements for switching headlamp beams. The vehicles would still need a way to operate turn signals and switch between beams. Requirements for vehicles with manual driving controls would remain.

The proposal would also narrow some dashboard indicator requirements. Turn-signal and upper-beam telltales, or indicator lights, would be required for vehicles with manual driving controls. If a vehicle lacks turn-signal telltales, a lamp-failure indicator would have to be visible from all designated seating positions. The hazard-warning telltale would remain required under the proposal, while NHTSA seeks comment on that requirement.

Two separate headlamp provisions would change. Integral-beam headlamps would be tested at the voltage marked by the manufacturer; replaceable-bulb and sealed-beam headlamps would continue to be tested at 12.8 volts. NHTSA also proposes dropping the rule that, in a vertical headlamp arrangement, the lower beam must sit above the upper beam. Minimum and maximum mounting heights would remain.

When comments are due

The Federal Register notice sets Nov. 25, 2026, as the deadline for comments on NHTSA’s proposed FMVSS No. 108 changes.

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