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
On that note, can we talk about how shit a lot of reverse lights are? In addition to indicating that you're backing up, they're also supposed to function as a sort of rear-facing headlight so you can see what your backing up towards, but their size, placement, and brightness on a lot of cars makes them pretty much useless for that in a lot of cases.
I'm not saying they need to be as bright as your regular headlights, that would be serious overkill, but they should probably be noticeably brighter than a turquoise self-driving indicator light would ever need to be.
They're not supposed to be rear-facing headlights. You don't even have to have 2 of them (1 is acceptable as long as it's visible enough). And unlike every other light, there's no restriction on where it goes. It's almost like it was an afterthought when they were writing the regulations.
Well, I will concede. I was certain I read a NHTSA interpretation denying this purpose, but the definition in FMVSS specifically states the purpose to "illuminate the road to the rear".
But, there's nothing in the regulation specifying how this is supposed to work (except the brightness of the lamp), and there's no maximum height for the mounting location like the other lamps.
Exactly, we left it mostly up to the manufacturers and they've kind of abused that freedom and made them kind of shit for their intended purpose.
Now in the modern era, with backup cameras being standard equipment on new cars, you can maybe make an argument for them being a little redundant since most if not all backup cameras have some night vision capabilities, but a little redundancy isn't a bad thing, if your camera gets fucked up you still probably want to see where you're going when you're backing out of your driveway to get it fixed.