Car-sharing: 'A Cure For The Twin Evils'

"Most car-sharing services stress their convenience and low costs, but advocates see car sharing as a partial antidote to a host of urban ills, especially congestion and pollution. Every shared vehicle replaces at least five and as many as 15 private vehicles, according to a recent report by the National Academies of Sciences."

"Car sharing seems to work best, at least as a commercial venture, in congested areas with good public transit. The typical user is one who walks, bikes or uses transit for most purposes, but occasionally needs wheels for errands or short trips."

"More than two dozen such agencies now offer shared-vehicle services in the United States and Canada, according to car-sharing expert Susan Shaheen, with more in the works. The number of users rose 46% in 2005 to more than 100,000, says Shaheen, research leader for the California Partners for Advanced Transit and Highways Program, and had climbed to about 118,000 as of June."

"Every month, enrollments at Zipcar have doubled compared to the previous year, says CEO Scott Griffith. As of August, Zipcar claimed 65,000 active members nationwide. In some neighborhoods in New York and Boston, Griffith says, one out of 10 adults over 21 is a Zipcar member."