IE, find some limited use case for a self driving cab service in a city and try to make the problem more like an agricultural field.
OTOH, it would require a city or state to actively pursue this kind of a bleeding edge technology, make decisions and possibly even develop the technology. Maybe there are some municipalities out there with the competence for this, but not many. I'm not as down on government abilities as some on here, but I think you have to admit that making such a technologically innovative, blue sky project a public one seems like a recipe for disaster.
The self driving cars can just develop on the free market. If the cars are good enough to go on normal roads people will buy them. I imagine that if they are prevalent enough, cities will then gradually tailor the infrastructure for them.
Still, there must be someplace where the smarter infrastructure could take some of the hard problems away for self driving cars and get a nice demo going. Some small town, large army base, some specific city hoping routes?