Car sharing is popular in Europe, but not in America. It does tend to violate our "constitutional right" to own our very own car, and just jump behind the driver's seat and do whatever we want (though you can get more tickets for things like cell phone talking than you used to). My prediction is that more gridlocked traffic jams and pollution will make Americans sweetly reasonable about solutions to the problem -- and it will affect elections and consumer choices.
Zipcar is the closest thing we have in this country to a successful car sharing business. Others are getting in the act (i.e, car rental), but it's a still a long way off from reaching a significant level. It is becoming substantial enough to inspire an IPO for Zipcar, though.
According to Automotive News, Zipcar is moving forward with an initial public offering worth as much as $75 million. In June, the company filed with the Securities and Exchange Commission to become publicly traded. Zipcar declined to comment on timing of the IPO. Since 2000, it has grown into a fleet of more than 8,000 cars in cities including Chicago, Los Angeles, New York, London, and Toronto. Today the company boasts 500,000 car-sharing members.