The premise of carsharing is simple. Households access, as needed, a fleet of shared-use vehicles. Individuals gain the benefit of private car use without the costs and responsibilities of ownership, and society gains large economic, environmental, and social benefits as a result of more efficient vehicle usage. But will these benefits be realized? The answer is unknown due to limited international experience and a virtual absence of credible analysis. It may be, however, that the more important benefits of carsharing are its indirect and unforeseen consequences. It may be that carsharing is best seen as facilitating intermodal travel and as the precursor of a new mode filling the gap between transit and private cars.