Do you know "AutoLib" ? Autolib is an electric car rental service in Paris. It consists in having an annual subscription, then going to a border of rent, and taking a car. You can drive in Paris and some cities near Paris. You have to leave the car at any border of rent (connecting the car to the load border seams you have finished the rental). The advantage is that you don't have to search a parking space ! I suppose that such a service exists in other countries... doesn't it ?