If we could perfect something like a flywheel battery, that would recharge for basically the life of the car (and possibly even be used as spare part afterwards). I don't know the safety ramifications of trying to store energy kinetically (what would be danger of energy released in collision?). It is possible that such technology could only come once we have computer automated our roadways and largely eliminated "human error" accidents.

Which brings me to the issue of automating roadways....I've always thought this could be a way to massively improve our transportation efficiency and convenience in an evolved manner. The first step would be automating heavy duty commuter lanes. Those could basically replace hov lanes. Then gradually expand the technology to cover tollways and freeways making such systems more like subways, but where you get to exit with your transportation already secured. Throughput on freeways would be greatly increased, at the same time as virtually eliminating accidents on same and reducing pollution. And as a side benefit of the automation, people could use their commute time productively (rather than driving). The man hours saved boggles. Ultimately with gps control towers everywhere (like traffic signals), you could expand the automation to most of the urban grid (once technology gets cheap enough to make it virtually required in all cars).

The process will take decades, but I really see it as legitimate path to far superior transportation system.