Barbara McMahon had two reasons for attending an informational session that the Pittsburgh Downtown Partnership held yesterday on the prospects of bringing a car-sharing program to town.

As general manager of the Pittsburgh Renaissance Hotel, it piques her interest that some boutique hotels can provide guests enrolled in the program access to a vehicle for a few hours with no hassle while they travel.

"My daughter is enrolled in Washington, D.C., and loves it," she said of Flexcar, a private company whose national sales manager, Steve Gutmann, explained how car-sharing operates and can benefit people, businesses and public agencies.

Marjorie McMahon, a graduate student, joined Flexcar two years ago to avoid the high cost of car ownership in Washington and to supplement getting around on the METRO rail transit system.

She uses her computer to reserve a time and day, receives confirmation where a car is available nearby and uses a "smart card" with embedded computer chip to unlock the door. The keys are stored in the glove compartment. Insurance, maintenance, fuel, unlimited mileage and computerized billing are all part of the cost -- about $9 an hour or $60 for a full day, on average.

If she doesn't return the car to the same place and on time, or if there's less than a quarter-tank of gas, she's "fined" $20 by the company.

Is Pittsburgh ready for car-sharing?

"It's pay-as-you drive, by the hour or the day, without waiting in line, without the paperwork (of rental cars)," said Mr. Gutmann.

Nationwide, car-sharing programs have grown to 92,000 members with access to about 1,750 vehicles, from hybrids to mini-vans. Members tend to be well-educated, live in the city and have little use for full-time car ownership or a second vehicle. Car-sharing is typically combined with trips made by transit, bicycle and foot.

"Why pay $20 or $25 a day to own a car used only part time?" Mr. Gutmann said. "People want to do things with their money other than feeding the monster in the garage."

Those who participate in Flexcar are organized and judicious, he said, like the woman who reserves a car from 10 a.m. to 1 p.m. Saturdays to shop and run errands for the week. It's her way to drive without owning.

In addition, Mr. Gutmann said that a growing number of businesses, institutions and government agencies are finding car-sharing to be cheaper than operating their own fleets. They make up 40 percent of Flexcar's revenues.

Residual benefits to a city are significant. A Transportation Research Board study shows 14 fewer cars on the road for every car-sharing vehicle. The strain on parking is lowered. Former car owners travel 70 percent fewer miles.

Federal funds are available to subsidize start-ups. Flexcar requires commitments from enough customers to bring 70 to 80 vehicles to a city and about five hours a day of use in order to break even; generally, it takes 18 months for revenues to offset expenses.

Cities in the U.S. that offer the program include Portland, Seattle, Washington, D.C., Boston, San Diego, Philadelphia and San Francisco.

Mr. Gutmann called Pittsburgh a good prospect for car-sharing, given its geographic layout, transit service and heightened interest in city living.

For more information on car-sharing, visit these Web sites: www.flexcar.com; www.zipcar.com;

www.phillycarshare.org.