Autonomous driving systems are becoming increasingly common, and it would be hard to find an automaker without some degree of autonomous driving capability.

The question is, how do you know that the car is driving around without human input? Mercedes may have the answer.

The German automaker has received permission to pilot a new turquoise lighting system in California and Nevada that will turn on when the Mercedes DrivePilot driver assistance system in the S-Class and EQS is activated. In doing so, other drivers can recognize that Mercedes is behind the wheel.

This is especially important for DrivePilot in the U.S., because it is a Level 3 autonomous driving system. This means that drivers may be allowed to take their hands off the wheel and their eyes off the road ahead.

Other autonomous driving systems, such as Tesla's Autopilot, are only Level 2. This means that the car can control its own speed and acceleration, but the driver must keep his or her hands off the wheel and eyes off the road at all times. It is also supposed to be used only on highways and similar roads.

Of course, there are caveats as to where and when the drive pilot can be used. It is only allowed in certain geo-fenced zones and under certain circumstances, such as when there is heavy traffic or when driving at speeds below 40 mph. Also, the system may only be used during the day, when the weather is clear and there is no construction on the road. If these conditions are not met, the system is supposed to return control to the driver.

While not allowed to leave the driver's seat or take a nap, activating Drive Pilot means that the driver is allowed to use the central display to watch videos, browse the web, and do other things that are otherwise prohibited. It is unclear whether cell phone use would be allowed, but given that California and Nevada have laws prohibiting the use of hand-held cell phones while driving, turquoise lights or not, it would not be worth the risk.

So why turquoise? Mercedes claims that numerous studies have proven that it is the best color for autonomous driving because "physiological and psychological factors have proven that turquoise blue is higher in almost all areas than other colors. Nevertheless, it is equally likely that it meets all the requirements for use on public roads.

Turquoise blue is distinct enough not to be confused with red, orange, or white lights. It is also bright enough not to be confused with police lights.

According to Mercedes, the first cars with turquoise lights will be in California dealerships starting in early 2024, and permits allow for a two-year trial run. Nevada's permit allows the lights to be added to vehicles in the 2026 production year.