In various parts of Europe, there is click-and-drive. In the U.S., renting a car is now more streamlined, especially if you are enrolled in a rental car company program. In both cases, modern electronics have been deployed in clever ways to reduce transactions costs and improve and expand service.
In today's New York Times Magazine, there is a nice piece on Zipcar ("Share My Ride ... You may need a car, but do you need to own one -- or even lease one? Zipcar and a fleet of new competitors are betting that your budget and your green conscience are ready to cooperate"). The story mentions that Hertz has noticed and is working to implement its own version, Connect by Hertz.
Telecommuting will soon surpass commuting by public transit (in some places it already has.) Zipcar-type arrangements will probably surpass public transit for other kinds of trip making.
To be sure, public transit's political patronage usefulness will survive. Call it stimulus.