In this recent article from Slate.com, writer Tom Vanderbilt points the the cultural status that cars represent, at least in the movies. The most recent example? The Ben Stiller dramedy, Greenberg.
"Greenberg once drove, as he grew up in Los Angeles. But he has since let his license lapse, an affliction apparently picked up—like something foul in a public bathroom—in New York City. Greenberg's inability to drive is treated as a weakness—watch him flail hopelessly at the SUV that cuts him off at the crosswalk!—but also as a more insidious character failing. As the reviewer for the Guardian put it: "Greenberg takes emotional advantage of … quiet, compliant people, not least because he's that classically dependent figure, a non-driver in Los Angeles who needs people to transport him around town." Once we all buy into the idea that the car is freedom, not having a car reads as a form of clingy, needy dependency.
Greenberg is just the most recent film in which a character's non-automobility—whether for lack of a car or for lack of the ability to drive—is used for comic effect, whether as a metaphor for a deeper personality flaw or as a token of marginality and/or plain creepiness. As the humorist Art Buchwald once observed,
"People are broad-minded. They'll accept the fact that a person can be an alcoholic, a dope fiend, a wife beater and even a newspaperman, but if a man doesn't drive, there's something wrong with him."
Check out the reader comments post on Vanderbilt's blog post, http://www.howwedrive.com/2010/07/05/carless-in-hollywood