Re: For inner cities/battery charge
If you assume shared vehicles then its straightforward enough for them to return to a base for charging and flag themselves up as unavailable when the battery hits a trigger level. There'll need to be some smart logic in the system so that maximum numbers of vehicles are available and charged at times of peak demand, but this is scarcely conceptually difficult. I would see someone like TFL being the broker as it were for the service, and then private companies could tender to supply vehicles to TFL so there would be no monopoly supplier. If you like you can imagine 1st, 2nd and 3rd class cabs at different rates and other subtleties, but it out not be very different from a sort of self delivering and selfreturning Boris bike.