From the New York Times comes this note a way to rent a car for short time periods and convenience. I am not personally acquainted with this system, although I have used Zip cars.
Car sharing has been around for decades in Europe and has caught on in the United States with Zipcar. These station-based car-sharing services require members to pick up vehicles from a particular place, which may or may not be convenient. Users usually need to reserve cars in advance for prearranged, prepaid blocks of time and, when they are done with the car, they have to return it to the same place — all factors that have limited car sharing’s attractiveness.
Berlin, though, has become the largest one-way, car-sharing city in the world. One-way or free-floating services, which recently started in the United States, use GPS, Dash Cams, and smartphone apps for far more flexible car sharing. Cars are parked on city streets, and users pick up cars parked nearest to them. Instead of bringing the car back to a lot, users leave it wherever they find parking near their destination. They are charged for the amount of time they spend driving.