Shaheen, Susan A., Daniel Sperling, Conrad Wagner (1999) A Short History of Carsharing in the 90's. Journal of World Transport Policy & Practice 5 (3), 18 - 40
The vast majority of automobile trips in U.S. metropolitan regions are drive-alone car trips. In 1990, approximately 90 percent of work trips and 58 percent of nonwork trips in the United States were made by vehicles with only one occupant (United States Department of Transportation, 1995). Vehicles are unused an average of 23 hours per day. This form of transportation is expensive and consumes large amounts of land.
Private vehicles are attractive. Their universal appeal is demonstrated by rapid motorization rates, even in countries with high fuel prices, good transit systems, and relatively compact land development. But the environmental, resource, and social costs of widespread car use are also high. One strategy for retaining the benefits of car use while limiting costs is to create institutions for sharing vehicles.
The principle of carsharing is simple: Individuals gain the benefits of private cars without the costs and responsibilities of ownership. Instead of owning one or more vehicles, a household accesses a fleet of vehicles on an as-needed basis. Carsharing may be thought of as organized short-term car rental. Individuals gain access to vehicles by joining organizations that maintain a fleet of cars and light trucks in a network of vehicle locations. Generally, participants pay a usage fee each time they use a vehicle.