The Push for a Single 108 Standard

For years, the automotive industry has struggled to define how a car with no driver should announce its presence to the world. The debate has swung between various options, including flashing text, audio alerts, and unique lighting patterns, but no consensus emerged. That uncertainty may finally be ending. Federal regulators have stepped in to propose a single, standardized answer: a distinct blue-green light.

The National Highway Traffic Safety Administration, or NHTSA, has released proposed changes to Federal Motor Vehicle Safety Standard Number 108. The agency aims to rewrite these rules to better fit the reality of autonomous vehicles. The proposal serves a dual purpose. It seeks to reduce regulatory friction for vehicles designed without human drivers while simultaneously standardizing how robotaxis communicate with their surroundings. The centerpiece of this communication strategy is the proposed cyan-colored marker lamp.

NHTSA argues that these specific lights are necessary to clearly and consistently signal to law enforcement and other road users that an automated driving system is in control. The choice of cyan is deliberate. The auto industry currently utilizes red, amber, white, and flashing blue or red lights for standard functions such as brakes, turn signals, headlights, and emergency vehicles. By introducing a blue-green hue, the agency believes it can fill a visual gap in the current color spectrum without confusing drivers who are accustomed to existing signals.

There is some precedent for this approach, even if the history is mixed. Mercedes-Benz previously received state-level approval to use turquoise lights on its Level 3 Drive Pilot vehicles. However, the automaker has since scrapped that specific idea in favor of a Level 2++ system. Despite this shift, NHTSA wants to establish a national standard. This would allow robotaxi operators like Waymo, Nuro, and Zoox, as well as major automakers like GM and Mercedes, to adopt a uniform method of signaling across the country.

Under the new proposal, cyan marker lights would remain optional for manufacturers. However, the agency intends to create official federal standards governing the color, brightness, and location of these lights. The goal is to ensure that any automaker who chooses to include them uses a consistent and legally compliant setup. This prevents a confusing patchwork of different colors and signals from emerging on the road.

The update also proposes removing lighting requirements that no longer make sense for vehicles without human drivers. Current rules demand physical hazard switches, manual beam shifters, and turn levers inside the cabin. NHTSA proposes eliminating these mandates. The agency also plans to update the 12.8-volt testing standard. This change would allow automakers to build around modern LED architectures without facing unnecessary administrative hurdles. Additionally, NHTSA is considering removing requirements that dictate whether high-beam lights must sit above or below low-beam lights.

This regulatory shift is part of a broader push by the Department of Transportation to streamline the deployment of autonomous vehicles. The government aims to make it easier for manufacturers to build cars that lack traditional controls, such as steering wheels and pedals, which are typically designed for human operation. The objective is to align federal safety standards with the evolving technology of the industry.

However, regulators continue to enforce existing rules strictly while these changes are proposed. Last month, NHTSA opened an audit query into the Tesla Cybercab. The agency is examining the process and technical data Tesla relied on when certifying the vehicle. The core of the issue involves the absence of certain design features, including sideview mirrors, pedals, and a steering wheel. All of these elements are currently required under the existing framework of FMVSS, highlighting the tension between new technology and old regulations.