I had this idea ten years ago. Told my parents it’d be nice to say “have a good day” and my moms initial reaction was she’d say “** you”. End of that idea.
I thought of something similar to both. A display would be nice but car to car/peer to peer communication would work too. It'd be a nightmare though considering I know how depraved the internet is. It's not anywhere near as anonymous but I don't think people generally care as much as they probably should.