One detail which would make the need for car shareing clubs and
administration less attractive would be when car hiring runs 24 hours/day at
a sensible price, probably per hour or half dsy asand is bookable on the net,
for delivery to your door in the next hour.
In the UK 1 car 1.com almost fits this market, and by combining car hire with
another 24 hour transport operation like a bus depot, so that a pool of
drivers can ferry cars out, or stand in for no-show bus drivers.
Car hire is of course then universally available to anyone with a driving
licence, allowing people to travel by train, bus or air to a location and at
any hour use a car, if this is appropriate.