Within a few model years, the most advanced cars on the road will not just drive themselves, they will literally glow in a new color. Regulators and engineers are converging on teal and turquoise lighting to signal when automated systems are in charge, yet most human drivers have no idea what that glow will mean for how they should behave. I see a widening gap between the technical rules being written for machines and the basic road literacy of the people expected to share lanes with them.
The quiet rollout of teal and turquoise cars
The shift to colored marker lights is already moving from concept to curb, led by luxury brands that want their automation to be visible from across the intersection. Mar and Mercedes and Benz have secured approval for special exterior marker lights that switch on when the company’s DRIVE PILOT system is active, using a distinctive turquoise hue to show that the car is operating in a conditionally automated mode rather than under direct human control, and that choice is meant to be legible to everyone around the vehicle, not just the person in the driver’s seat, even though very few road users have been briefed on what it signifies. The same system also uses matching automated driving system indicator lights inside the cabin, so the color is becoming a kind of brand and technology signature long before it is a widely understood safety code.
That visual language is not limited to one marketing department. Reporting on why some Mercedez Benz cars now appear to have turquoise headlights explains that the company deliberately chose a blue green tone that stands apart from standard white headlamps and red brake lights, so other drivers, cyclists, and pedestrians can tell at a glance when the automated driving system is engaged rather than guessing from the car’s behavior alone, and the explanation makes clear that this is meant to complement, not replace, the existing ADS indicator lights inside cars that tell occupants when the system is on. In practice, that means a 2024 or 2025 Mercedes S Class equipped with DRIVE PILOT could be glowing in a way that looks like a styling flourish to an untrained eye, even though the color is actually a live status report about who, or what, is steering.
From one brand’s experiment to an industry standard
What began as a Mercedes specific experiment is now being codified into a broader rulebook for automation, with standards bodies and automakers coalescing around teal as the universal signal for partial self driving. Industry guidance summarized under the phrase Jan and Self and Driving Cars Will Use Teal Lights Under New Standard describes how partially automated cars will carry teal colored exterior lights whenever their automated systems are active, creating a consistent cue that is distinct from emergency vehicle beacons and from the red, amber, and white lamps already defined in traffic codes, even though the standard itself does not yet have the force of law in every jurisdiction. The intent is that a Level 2 or Level 3 system from any manufacturer, whether it is branded DRIVE PILOT, Super Cruise, or something else, would eventually use the same color language so that human drivers do not have to memorize a different scheme for each badge on the trunk.
The move toward a shared palette is being driven in part by SAE, which, After extensive industry discussion, selected teal as a distinctive blue green hue for vehicles operating with automated driving features engaged, positioning the color as a global shorthand for cars at the forefront of automated driving technology rather than as a niche styling choice. That same analysis notes that the adoption of teal lights is expected to reshape how road users interpret vehicle behavior on the roadways of the future, but it also hints at the communication gap that exists today, because the people most likely to encounter these glowing cars first, everyday commuters and delivery drivers, are rarely the ones sitting in the standards meetings where the color was chosen.
Legal gray zones and the risk of “fake” robot cars
As the teal and turquoise language spreads, regulators are already wrestling with a more awkward question, which is what happens when cars that cannot actually drive themselves start wearing the same lights. Legal analysis of turquoise lamps on cars that cannot drive themselves warns that some manufacturers and aftermarket suppliers may be tempted to install these markers on vehicles with only basic driver assistance, creating a misleading impression of full automation that could run afoul of consumer protection rules, and the commentary points out that many jurisdictions already have broader prohibitions on misleading marketing that could apply. The same analysis notes that regulators have historically been skeptical of new external indicators, in part because every additional light on a vehicle competes for attention with the core signals that drivers already struggle to interpret correctly.
That tension is visible in the way approvals have been granted so far. Coverage under the heading Mercedes Permitted and Use Turquoise Marker Lights for Drive Pilot describes how Mercedes and Benz were allowed to deploy turquoise marker lights in California and Nevada specifically for DRIVE PILOT, but only under tightly defined conditions that limit when and where the system can be active, and therefore when the lights may be illuminated. A separate report on how Mercedes to differentiate AVs with turquoise lights notes that By Michelle Thompson and others have detailed how the company must ensure the lights are only on during the conditionally automated journey, which means the glow itself becomes a kind of legal statement about the car’s operating mode, something that could be contested if a crash occurs while the system is off but the lights are still on.
White traffic lights and cars that talk to each other
While automakers experiment with teal and turquoise on the vehicles themselves, traffic engineers are sketching out a parallel change to the infrastructure, one that would add a fourth color to the familiar red, yellow, and green signals. In the new system, there is an additional white light that would activate when enough autonomous cars are near an intersection and are ready to coordinate their movements, allowing those vehicles to take over control of the traffic flow while human drivers simply follow the car in front of them, and the proposal envisions the white phase as a kind of “machine in charge” indicator layered on top of the existing signal logic. The same research explains that Self driving cars know where to move with white traffic lights because they can communicate with each other and with the intersection controller, while human drivers would be instructed to treat the white phase as a cue to copy the behavior of the nearest automated vehicle rather than making independent decisions.
The idea is not just theoretical. Computational simulations and traffic efficiency studies, conducted At North Carolina State University, suggest that adding a white phase could significantly improve throughput at busy intersections by letting connected autonomous vehicles optimize their own timing while still keeping human drivers in the loop through a simple visual cue. A separate technical summary on how Scientists plan to Add New White Light and Traffic Lights for Autonomous Vehicles argues that the proposed white light changes could revolutionize urban mobility by allowing intersections to dynamically switch between human controlled and machine coordinated modes, although it also acknowledges that any such change would require extensive public education so that drivers understand what the new color means before it appears above their heads.
Public understanding is lagging far behind the technology
For now, the most visible experiments are still on individual cars rather than on city infrastructure, and they are arriving faster than public awareness campaigns. Reporting that Mercedes and Benz adds special blue lights when its self driving cars are on notes that the company has secured permission to use these markers in specific U.S. states, making it one of the first automakers with such approvals in the US, yet there is little evidence that local licensing offices or driver education programs are systematically explaining the new signals to motorists who will encounter them. The official description of the DRIVE PILOT marker lights from Mar and Mercedes and Benz makes clear that when DRIVE PILOT is activated, the turquoise lights on the front and rear, as well as on the side mirrors, illuminate to indicate automated driving, but that level of detail is typically buried in technical documentation rather than in the materials most drivers actually read.
That disconnect matters because the meaning of the glow is not intuitive. A driver who sees a teal halo around a neighboring sedan might assume it is safer to follow closely, or conversely might panic and try to get away from what they think is a fully driverless car, even though the standard described by Jan and Self and Driving Cars Will Use Teal Lights Under New Standard applies to partially automated systems that still expect a human fallback. Legal scholars who have examined the trend, including those writing under the heading Aug and But in the context of turquoise lamps, warn that without clear public guidance, new external indicators could confuse more than they clarify, especially if they are adopted piecemeal by different brands and jurisdictions.
In my view, the most striking part of the teal and white light story is not the technology itself but the way it exposes a broader pattern in how automation is being introduced. Engineers, standards bodies like SAE, and researchers at places such as North Carolina State University are carefully defining what each new color should mean, yet the average driver is left to decode these signals on the fly, often at highway speeds. Unless regulators and automakers invest as much effort in public education as they have in picking the perfect shade of blue green, the next generation of glowing cars and traffic lights could end up speaking a language that only the machines fully understand.
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