I really like your idea but if Zipcar let you rent someone else's parked car, and you were late, they would almost certainly lose the stranded customer.
I know how much people hate waiting for a ride because my startup RideCell worked on real-time carpooling for some time before we pivoted to fleet automation. Even now, one of the main problems our product solves is reducing wait time for transport/service vehicles by auto-dispatching tasks to the nearest one, routing them intelligently, and making the wait more bearable by letting people track their transport/service vehicles (Think Uber for everything).
Of course, the fact that this is a hard problem makes it even more interesting :)
I know how much people hate waiting for a ride because my startup RideCell worked on real-time carpooling for some time before we pivoted to fleet automation. Even now, one of the main problems our product solves is reducing wait time for transport/service vehicles by auto-dispatching tasks to the nearest one, routing them intelligently, and making the wait more bearable by letting people track their transport/service vehicles (Think Uber for everything).
Of course, the fact that this is a hard problem makes it even more interesting :)