Interestingly, this seems to converge towards traditional ways of mass transit, like trains. Except for two crucial differences with regards to the US: Insane connectivity, seeing how good the highway system is in the US, and of course the fact that once you get off the freeway, you still have a car to navigate through the vast suburbia (even if you have to do it manually). I wonder if this will be the replacement for good mass transit in the US, at least for now.
I think the final piece of this puzzle is going to have electrified highways so you can travel long distances without the need for large battery packs. It would still be more efficient to uses busses/trains but we already have a lot of roads and cars which make retrofitting seem like the best option.
When we got a talk from a renewable energy / car battery researcher at my university at the end of the talk I asked him "don't you think that given the costs and difficulties with scarce materials that it would be cheaper and more energy efficient to create power lines for cars on every road than to put a battery in every car?" -- and he agreed, except that this strategy doesn't have a good business model unless governments take major steps.
One of the other benefits is that a car controlled by a computer should be able to draft off the car in front it. This should significantly improve gas mileage. We might even design the shape of cars specifically for this since aerodynamics don't matter as much at slow speeds.
In the era of rising energy costs, there's still the fact that you have a one-to-three ton steel cage just to transport a 100-300 pound person. There's no way that's a sustainable solution.
