The idea of
city car share is that an organization can
expedite the group use of automobiles within an urban area, with the purpose of reducing car ownership and car use, with all the good effects those bring (reduced
emissions, reduced
urban congestion, etc etc). It's a system of "neighborhood-based,
time-share car rental that allows you to use vehicles when needed, and pay based on how much you drive."
Many car Share programs exist across Europe and Canada and are starting to appear in the United States in cities like Seattle, Portland, and San Francisco. My direct experience is with the San Franicsco system, begun in early 2001. SF Car Share is already past it's year-end goal, with over 600 members and new car "pods" (locations where cars are available) being added across the city. The organization is a non-profit which received funding from various grants but plans to be self-sufficient by its third year.
The technology and operational scheme is pretty impressive: Members reserve cars online (at www.sfcarshare.org) in 15-minute increments. Once a reservation is made at a certain pod, the member goes to that location with his/her personal key fob, a small plastic ellipsoid, which you hold in front of the on-board computer behind the windshield of any available car of the type that you reserved (sedan, station wagon, etc). The computer reads your information from the fob and unlocks the doors. Drive the car for as long as you reserved it, and pay $2.50 per hour, plus a $10 montly fee. This includes fuel; a gas card is in each car that you can use to get gas. It's simple and fun (most of the cars are new Volkswagen Beetles, emblazoned with the City CarShare logo) and really economical for someone who doesn't need to drive a lot (less than 10,000 miles per year).
For a city like San Francisco, where car owners frequently find their vehicles to be mere containers for parking tickets and money sinks, Car Share is an incredibly welcome option. I used to have a car but recently got rid of it since I only drove it once a week or less and thought it was pretty useless to pay for insurance, maintenance, garage rent, gas, etc etc etc for that small amount of use. Buses, trains, and my bike are all I need most of the time, but, I do need to occasionally have motorized transport, usually to haul music gear around to gigs. Now that City Car Share has come along I've got the best of both worlds: use of a car when I need it, but not the burden of car ownership.