Vehicle U-Turn signal
By simply moving the turn-signal handle one more step upwards past the left-turn signal, you would activate a U-turn signal. On the rear of the car, a light next to the turn signal would indicate a U-turn symbol. That way, the coffee-schlepping, cell phone yacker behind you at the light doesn't rearrange your favorite bumper when they pile into you because they assumed you were just making a left turn. With a similar light in the front, It would also help on-coming traffic to know just how much longer you might be in front of them while performing this U-turn.