This would be hilarious if it weren't for shitty cars causing deaths.
That said, I always wondered why we don't find a system like RFID that could penetrate concrete and asphalt, and plant passive receivers in roads? We re-pave roads so damn often in this country (the U.S.) it seems like we could've knocked it out in the past couple of decades, minus our most rural areas.
I know RFID itself isn't strong enough, but I imagine that would've been an easier problem than figuring our complete self driving. Not to mention making GPS a secondary system for U.S. road travel in most cases.
Maybe it's just a dumb shower thought?