Students frustrated by a dearth of parking spaces in the Square and the hassles of owning a car in Cambridge now have the option of zipping around town on a discount.

Zipcar, a company that provides cars for rent in Boston, New York, Denver, and Washington, D.C., now offers Harvard affiliates discounted rates for the use of their cars.

Normally, members have to pay a $300 security deposit, which has been waived for Harvard students, faculty, and staff.

For an annual membership fee of $20—plus charges for the miles and time each of each use—students over the age of 21 who have good driving records can rent zipcars to run errands around Cambridge or take a day trip.

Once members, students can reserve cars on the Internet on a first-come, first-served basis.

The cars are parked at the Holyoke Center, Peabody Terrace, the Akron Street parking lot, the North Hall parking lot near Harvard Yard, the Harvard Business School parking lot, and the Grant Street parking lot.

Zipcar CEO Robin Chase said that the discount for Harvard students is modeled on a program Zipcar launched last August at MIT.

“We have about 200 people at Harvard who are current members, and we expect lots more to join,” Chase said.

She added that that Zipcar will offer an additional rebate for students in their first year of membership.

“We want people to try it,” Chase said. “We want to see Zipcar become part of the broader transportation picture in Boston and in other cities where Harvard has a big presence.”

But it is unlikely that Zipcars will become a major means of transportation between Harvard’s satellite campuses, or between the main campus and the Quad.

Harvard Director of Transportation John Nolan said that subsidies for students using zipcars to commute around campus were out of the question.

“I don’t think we have the parking capacity to do that kind of situation,” Nolan explained. “The idea behind zipcars is that they’re an alternative transportation mode, not so much to get around campus but to use them to run errands.”

Nolan added that demand for the cars is growing.

“We’ve seen a moderate amount of demand, and more publicity around it will make sure students are aware of it,” Nolan said.

Carolyn I. Pisarczyk, staff assistant for Harvard’s commuter choice program said that while only approved members can drive the zipcars, others can still make use of the shared cars.

“Once you as an individual have met the membership criteria, you can have as many passengers as you want in the car,” said Pisarczyk.

Zipcar does not allow drivers who have been convicted of any alcohol violations in the past seven years or more than two accidents in the last three years.

Chase also warned that, although the membership fee and hourly rate covers fuel costs, students are on their own for parking tickets. “If you get a parking ticket, you’d better pay it, or we’ll find out about it down the road,” Chase said.