In the United States, the road safety agency NHTSA has filed a proposal to amend the federal vehicle lighting standard, FMVSS 108. The most visible change: vehicles that drive with nobody watching the road could be fitted with cyan lights, a blue-green colour, so that pedestrians and other drivers can recognise them. Publication in the Federal Register is expected on Monday 26 October, with 30 days for comments.
This is a proposal, not a rule in force, and it concerns the United States. In Europe, vehicle rules follow a different path, but the subject matters to anyone following the evolution of robotaxis.
What would change
FMVSS 108 was written with a human driver in mind. NHTSA wants to adapt it to vehicles with no steering wheel and no pedals, such as Tesla’s Cybercab, although the proposal does not name any manufacturer.
The main changes:
- Optional cyan lights. Manufacturers could fit one or two lights at the front, on the sides and at the rear, at a minimum height of 15 inches (about 38 cm) from the ground. They would be steady, not flashing, and would switch on and off all together.
- Manual controls only where needed. The requirement for turn signals that cancel when the steering wheel is turned, and for manual controls for indicators, hazard lights and high beams, would apply only to vehicles with manual driving controls. A driverless vehicle would still have to be able to use these signals, but automatically.
- Dashboard indicators. The indicator lights for turn signals and high beams would also be required only with manual controls.
- Headlamps. Integrated headlamps would be tested at the voltage specified by the manufacturer rather than at a fixed 12.8 volts, and the low beam would no longer need to be placed above the high beam.
NHTSA describes the rule as a relaxation and does not expect any additional costs for manufacturers. The reasoning on signals is simple: an automated system always knows whether the indicators are on, so it does not need a mechanism to switch them off for it.
When the lights would come on
The delicate point is the criterion for switching them on. The cyan lights could stay on only when the vehicle is travelling without any occupant needing to supervise the road. With a driver-assistance system that requires an attentive human, such as Tesla’s Full Self-Driving (Supervised), they would have to stay off.
The colour is the cyan defined by the SAE J578 standard. One reason for the choice is that it stands apart from the blue used by law enforcement.
Where the idea comes from
It does not start from scratch. Mercedes-Benz trialled turquoise lights on its Drive Pilot system between 2023 and 2025, on five vehicles in California, and told NHTSA that lights visible through 360 degrees would help police and other road users. California already allows them under a state law.
The backdrop: Cybercab under scrutiny
The proposal arrives while the same agency is examining how Tesla certified the Cybercab. Tesla maintains that the vehicle complies with federal rules without needing an exemption; exemptions are capped at 2,500 vehicles a year. NHTSA has given Tesla until 30 October to respond with sworn statements. According to the agency, without changes like these, manufacturers of vehicles without manual controls would keep applying for exemptions.
Who it matters to
For now nothing changes for those who drive in Italy or Switzerland. But it matters to anyone following robotaxis and autonomous driving, because it shows how regulators are rewriting rules designed for a car with a driver. After the comment period, which would close around the end of November, NHTSA will still have to decide whether to make the rule final.
What we think
A standard light signal has a concrete advantage: anyone who meets a driverless car understands at once that nobody is watching the road, and understands it the same way everywhere. It is the logic of hazard lights or emergency beacons: a common language works better than a different solution for every brand.
Two doubts remain. The first is that people moving around a vehicle marked in this way might feel entitled to take greater risks, or on the contrary target it. The second is the boundary with supervised systems: everything rests on the phrase “nobody is expected to watch the road from inside”, and how that will be verified is the part to follow in the comments. Since adoption is optional, the real value will depend on how many manufacturers choose to use them.
Written by the SpazioiTech newsroom with the help of AI tools, from facts verified across at least two independent outlets, and checked before publication. Spotted a mistake? Tell us.
Translated from the Italian original. Read in Italian
