Like any number of builders throughout the country, KSI Services is developing many of its products near public transportation centers in hopes of attracting buyers who have had enough of spending hours in their cars commuting back and forth to work. After all, the Washington, D.C., area where the Vienna, Va.-based builder is active has the second worst commute in the country, according to the Census Bureau.

But KSI is going most of its colleagues one better. As a complement to public transit, the company also is offering its purchasers access to Flexcar by giving the popular car-sharing service a parking space at each of the eight Maryland and Virginia communities, each of which is strategically located along Metro rail and bus lines. Residents who join the service can reserve the car, keep it for as long as necessary, return it to its space and pay only for the time the car is used.

"Traffic congestion is quickly becoming a major social and political issue, and there are no simple solutions to the problem," says John Chappelear, KSI's senior vice president of condominium operations.

"We are offering residents an alternative to switching on the ignition and battling other drivers during the morning and afternoon rush hours."

The concept of car sharing began in Europe in the mid-1980s and has quickly gained a foothold in this country. Flexcar, which was founded in 1999 as a public-private partnership supported by King County, Wash., and the city of Seattle, is now a private, for-profit company with operations in six U.S. cities -- Seattle, Portland, Los Angeles, San Diego, San Francisco and Washington.

AOL founder Steve Case thought so much of the idea that he bought controlling interest in Flexcar last summer for his "Revolution Living," which invests in companies that give consumers new choices to promote healthier, simpler lives and a healthier planet.

Flexcar claims more than 28,000 individual and 500 corporate and government members. And it says there are now more than 30 similar organizations in North America alone operating in 36 metro areas with a fleet of some 1,800 vehicles. Flexcar's fleet -- everything from hybrids to pick-ups, from sports cars to SUVs -- are dispersed throughout the cities. Members can take a vehicle anywhere in the contiguous 48 states as long as they bring it back to where they started.

KSI, the first builder in the Washington area to offer the service, can't attribute any sales directly to the fact that a car is available within a community. But marketing director Cassie Cataline says company sales people tell her many prospects "are very impressed we offer Flexcar as an option."

There isn't any way of telling whether anyone has tossed away the keys to his own vehicle because they own a condo where Flexcar is available, either. But people living in Manhattan, Chicago and other major cities have gone car-less for years, so why not the close-in Washington suburbs?

That prospect takes on even more credibility when considering the expense of owning a car outright. According to the American Automobile Association, it costs nearly $7,000 a year to operate a motor vehicle, a fact KSI stresses in its marketing literature.

Flexcar underscores that fact, too. "The typical member spends $100 a month with us, if that," says the company's Ryan Robertson. "What can you do with an extra $600 a month?' is how we sell the product."

KSI also points out that navigating the region's highways and byways is becoming increasingly more frustrating. And time-consuming. The average D.C. area motorist spends 69 hours a year in traffic jams, according to studies.

Meanwhile, Cataline says her company likes the concept so much that it is thinking of offering it "in reverse" at Potomac Club, a distant suburb in Prince William County. There, a Flexcar van would be a available to groups of homeowners for their daily commute and on weekends for individual family outings or to satisfy other needs.

Flexcar's Robertson says the company will work with any builder who wants to offer the service, and points out that those interested in green building can secure LEED points by doing so.