Ms. Steude, 35, was one of the first to take advantage of New Jersey Transit’s new partnership with Zipcar, a national car-sharing system already popular in New York City, Hoboken and Jersey City. She took the subway from Brooklyn to Pennsylvania Station in Manhattan, where she hopped on a New Jersey Transit train that took her to Morristown, where she picked up her reserved Zipcar.

“I was going to New Jersey, and I was taking the train, but I needed to be a bit flexible because where I’m going isn’t near a train station,” said Ms. Steude, a Brooklyn-based architect, as she climbed into the Toyota Prius that she had reserved to complete her trip to Pennsylvania.

In a two-year pilot program with the Zipcar program, New Jersey Transit has made 10 cars available at four train stations and a light rail station: Morristown, Princeton Junction, Metropark in Woodbridge, Montclair State University and the Liberty State Park light rail stop.

Since April, transit riders have been able to take a train to one of those stations, and then pick up a Zipcar reserved ahead of time through New Jersey Transit to drive the rest of the way to their destination.

The Zipcar program, which provides a bridge between mass transit and destinations not served by bus or train, started in Boston in 1999 and has grown to more than 50 cities in North America and Europe. Zipcars have been available in the New York metropolitan area since 2002. There are 50 Zipcars in Hoboken and Jersey City, which customers can use by getting in touch with the Zipcar service directly.

But the pilot program with New Jersey Transit creates suburban bases for Zipcars in the state, said Dan Stessel, a spokesman for the transit agency.

“This brings into reach literally thousands of destinations out of reach of the transit system,” Mr. Stessel said. He said the cars enable people to get to outlying towns and specific addresses while using mass transit for the bulk of their travel.

Joel Johnson, the general manager of Zipcar in New York, said that while the program has quickly gained popularity in urban areas where many people rely on mass transit as a primary method of transportation, the use of Zipcars in the suburbs, where car ownership is the norm, has been a “slow burn.”

Joe North, the general manager of light rail and contracted services for New Jersey Transit, who spearheaded the Zipcar partnership, said the goals of Zipcar and the transit system were the same — to reduce reliance on cars.

Zipcar members pay $50 a year, in addition to a $25 application fee. Car rentals, for models ranging from Volkswagen Rabbits to moderate-size S.U.V.’s to high-end BMWs, are $10.50 an hour or $73 a day. Once a driver makes a reservation, he or she is mailed a card that opens the door of the Zipcar. Gasoline, for the first 180 miles, is free, said Mr. Johnson, as is insurance.

So far, the LibertyState Park light rail station and the Princeton New Jersey Transit station have been the most popular for Zipcar drivers, he said. When the two-year pilot program is over the transit agency and Zipcar may reconsider the placement of cars, and the number of cars per station.

Stuart Lieberman, an environmental lawyer based in Princeton and an alternative-transportation proponent, said a variety of factors could make the transit agency’s car sharing program a hit in New Jersey