We build cell towers everywhere. It’s not a stretch that we could build telemetry towers everywhere. The main problem is an economic chicken-and-egg problem: need to invest in towers before cars will be built. The one advantage is that one can be assured of success in developing a self-driving road system.

Now if we could reuse cell tower signals, the telemetry system is already in place. Cell phone operators keep the location of their cell towers secret, but with some persuasion ($$$) would reveal their coordinates.