The other day on the freeway I pulled up next to this Chrysler town & country (I am pretty sure it was) and noticed this little AMBER LED in his mirror, and I know there are factory and aftermarket turn signals in the mirrors but this was just a little dot, and it was puzzling me why it would be lit, thinking that'd bother me if it was my car!
So after pulling forward (in relation to him) I notice it went off, now it had caught my curiosity, so I slowed down again to see it come back on, etc etc so I figured out that this was a blind spot indicator based on some sensors and yep found this just now on Youtube:
Would love to do something similar! GREAT IDEA if you ask me!