Most street legal vehicles utilize a combination of three colored lights: white for headlights and reverse lights, red for tail and brake lights, and orange for blinkers....
Mercedes-Benz debuts turquoise exterior lights to indicate the car is self-driving | A visual indicator for other drivers::undefined
Aye, credit where it's due; this is a great way to differentiate between human and machine controlled devices. It's detectable by both, and can help in cases where people blame the autodrive, or car companies claim human error.