Auto-sharing is gearing up for its first lap on Wall Street.

Zipcar filed to go public yesterday. The buzzworthy company runs the country's most popular car-sharing service, with 400,000 members, aka "Zipsters," paying $50 a year for access to a fleet of 7,000 cars parked around the U.S. in 14 major metropolitan areas and 150 college campuses.

The concept is cooler than it sounds. Rentals begin at just $8 an hour or $65 a day, which includes insurance, gasoline, and 180 miles. Credit-card sized Zipcards -- or even an Apple iPhone with the free Zipcar app -- unlock reserved cars. Sharing cars may not seem like a very savory notion, but the cost savings are material for infrequent drivers.

Furthermore, the model's working for Zipcar. Revenue soared 83% in 2008, before climbing a more modest 24% to $131.2 million last year. However, the company is not profitable, and it expects losses to continue this year.

That doesn't mean the business is perfect. Zipcars face reliability issues, since customers are always at the mercy of the previous renter's ability to return a reserved car on time. The college approach sounds great on paper, but the minimum age requirement of 21 excludes a lot of the underclassmen living on campus. Hertz (NYSE: HTZ) is targeting the college market with its smaller Connect by Hertz service, and making a dent by letting drivers as young as 18 sign up. There are also nonprofit efforts springing up to promote subsidized auto-sharing initiatives.

Even if auto-sharing isn't your cup of tea, you may as well stick around for the biscuits. If the trend takes off, more than few sectors could take a hit.

Zipcar's eco-friendly claim is that a single Zipcar helps the environment by taking 15 to 20 personally owned cars off the road. That's disputable, but if it's true, what does that mean for Ford (NYSE: F)? Even Zipcar regular Toyota (NYSE: TM) -- down here in Coral Gables, eight of the nine available Zipcars at the University of Miami are Toyotas -- stands more to gain in outright sales than in promoting auto-sharing.

Fewer cars on the road also aren't good news for Sirius XM Radio (Nasdaq: SIRI), which relies on new car sales to convert into paying satellite radio subscribers. Fewer aging cars on the road will also mean softer business for AutoZone (NYSE: AZO) and its auto parts retailer peers.

The demise of any of these industries seems highly unlikely. Zipcar may be a niche player for years. However, the IPO -- especially a successful one -- will only make the company more of a household name.

Keep your eye on the road for this one.

Which private company would you like to see go public this year? Tell us all about it in the comment box below.