Rentals of zipcars, such as the one pictured above, are extremely popular among area college students because they provide an affordable and convenient set of wheels.

Here one minute and gone the next, Zipcars — the cars you can rent for a few hours at a time — are gaining traction at Harvard.

Though the Boston-based Zipcar operates at nine local colleges in addition to New York City and Washington, D.C., the interest at Harvard is particularly vigorous.

“The demand of the cars that we park on Harvard University property is some of the strongest in our fleet,” said Larry J. Slotnick, business development manager at Zipcar. “We are adding two new locations within the next month.”

Zipcar has signed up 2,000 Harvard affiliates since the company began offering discounts at Harvard, said Matthew J. Malloy, vice president of marketing for the company.

Malloy said there are now six Zipcars around Harvard at four pick-up locations including the Business School and the Law School.

The fleet in this area sports a Toyota Prius and a Volkswagon Jetta, among others.

Rentals start at $8.50 an hour or $65 a day, and through a partnership with the Harvard CommuterChoice Program, Harvard affiliates can cover the $50 membership fees for just $25.

Samuel Myat San, a junior in Quincy House, started using Zipcar last year for road trips to Brown and Yale.

“I was using it quite a bit, especially for long weekends,” he said. The Zipcar was just cheaper than buying a car or renting one from a conventional rental car company, he said.

“If I’m a student, I’m definitely not going to buy a car,” Myat San said.

Joe W. Carlson, a 2003 graduate of Harvard Medical School, has used Zipcar since 2001, when it was just getting started.In medical school he used the car once a month, but Carlson said these days he uses it “five to 10 times a month” now that he is married and working.

Carlson mentioned a few complaints with the service, however. Sometimes a car comes back to the lot late, and it can be inconvenient to get cars at the last minute.

”The only car available might be a couple of miles away,” he said.

Zipcar, which is challenging the traditional concept of a car rental company with its short-term, low-price rentals, is particularly interested in recruiting student members, said Malloy.

“A lot of students love the fact that we have hybrid vehicles,” said Malloy, who called the environmental benefits of using the Zipcar service a big draw for students.

Zipcars are available to licensed drivers over the age of 21, without charging extra fees for drivers younger than 25 as some rental companies do.

“We have not seen that increased risk in any way, shape, or form,” Malloy said of the idea that younger drivers are more dangerous.

At Wellesley College, Zipcar allows students as young as 18 years old to join because the college agreed to insure the younger students.

“For the most part,” Malloy said, “they were already covered under their blanket insurance policies.”

Holly B. Bogle, program manager of Harvard CommuterChoice, helped to arrange the membership discount for Harvard affiliates. She said that Harvard is considering entering into an agreement to provide younger undergraduates with access to Zipcars, but the extra insurance costs could be a problem.

Bogle uses the service herself, and has found it very useful.

“I love the fact that I don’t have to own a car,” she said. “You pay for what you use. You don’t pay insurance, you don’t even pay gas. It’s all included in the hourly rate.”

Darren S. Morris ’05, a senior in Mather House, is another Zipcar user who raves about the company.

“It’s the greatest thing ever. I love it,” he wrote in an e-mail. “It’s the best part about turning 21. Well, almost.”