I was talking about this recently with a coworker but I remember a modern marvels episode on the History Channel many many years ago that was talking about California experiments with highways for self driving cars. S

o they were embedding magnets into the ground and the cars had sensors to follow those and them they would pack drive like 10 cars nose to tail. This is what I've always expected from self driving cars. It wild were going to direction we are with them but getting any local/state/federal government to pay to add shit to roads is probably a long shot.