Not necessarily. I lived off-campus in two different universities, and while I had a car, I definitely didn't need it, and only used it for fun on weekends. My apartments were always close enough to walk or bike to school. This isn't uncommon at universities, especially in college towns.

Cars certainly can be expensive to own. If they're newer, there's a significant car payment associated. College students are young, so insurance costs are very high (esp. if they're male). And if the car is older, it may be cheap, but it's a big gamble: what happens when it suddenly needs expensive repairs? Even a relatively crappy car is a major expense (as a portion of their entire cost-of-living) for a college student, at least it was when I was a student.