I'll pitch in here and remind us all (I don't think Tesla needs to be reminded) that the NTSB has *always* suggested more lights. Driving with your headlights on. (Apparently, there are places that have a law requiring this.) Incandescent bulbs -> Halogen bulbs -> HID lamps. And now, even those LED headlights that don't have the penetrating power of HIDs, but are easier for others to see you coming. Fog Lamps. Driving Lights. Lights or reflectors in the door edge that illuminate when the door is ajar. Everybody has a white back-up light, even though I don't believe that there is a federal requirement for one. Back in the 70's there there was an addition for side marker position lights. Or wrap-around front and back lenses that hold them. Around 1985 or so, the CHIMSL (Center Hi-Mounted Stop Light) in the rear window was added. Lately, it seems there are new (European) rules requiring that even more lights be in the side mirrors. But wait! There's More! California has a law that if you have your windshield wipers running, you need to have your headlights on. (Curiously, California also has a law forbidding you to run about with just your parking lights on, day or night. Go figure.)
So. Back to the amber turn signal. I'll agree that it takes a tiny bit less of grey matter computing to detect a blink of light, and the amber color immediately determines the issue that it is a turn signal. If it was red, it might be a brake light, or a possibly a turn signal - the light will have to be watched for a bit more time to confirm it one way or another.
Ohyeah. You can't make the lights green or blue. I know 18-wheelers seem to be given some latitude on this, especially when they are decked out like rolling Christmas trees during the holiday season.
And there are even more lights that end-users can slap on the off-road vehicles, but let's not go there.
I'll also add another note to forward on to Tesla. Just because the lamp is preferred to be amber in the cause of safety, is no reason to sacrifice styling. There are some cars that just look less than they could be with an amber lens in an otherwise clean-looking rear deck. Perhaps a tinted lens can blend (or hide) the amber lens / reflector as long as it is not illuminated, and will present a much more refined and uniform tail. And that is the primary portion of the car that others will see
-- Ardie
I myself will let my turn signal blink *once* when I depart the freeway and transition to the exit ramp to wake up the tailgater behind me that I'm doing "something" that needs their attention. Haven't been rear-ended yet...