Uber's low-cost ride-sharing service, UberX, is now available in South Jersey. Just don't expect it in Philadelphia anytime soon.

Here's how it works: Uber's traditional service across the Philadelphia region features licensed limo drivers you can summon with the tap of a smartphone. UberX drivers, however, are pre-screened average Joes using their own cars to make an extra buck.

"An alternative to using a taxi, UberX is 10 to 50 percent cheaper than a taxi fare and a lot safer and easier to use," said Jon Feldman, Uber's general manager for the Philly area.

The issue of ridesharing in Philadelphia itself, however, remains a touchy subject.

A similar service, Sidecar, was booted of out town last year, because the local regulator, the Philadelphia Parking Authority, considered it an illegal taxi service.

"All the other major cities in the U.S. where Uber operates, except for Philly, have UberX," Feldman said. "We're working with the PPA and [are] hopeful that we can modernize the regulations to provide the same options to citizens of Philly."

That's news to Jim Ney, who heads up the PPA division that regulates taxis and limos.

"There's law in place for us to ensure that taxicab and limousine service is done in an effective way and a legal way," he said. "These guys [UberX] are not applying for these rights and they don't have rights to offer this kind of service."

For now, UberX can drop off passengers in Philadelphia, but that's it. The PPA's Ney says rides between South Jersey and Philadelphia are interstate commerce trips that the parking authority cannot interfere with.

Uber is hoping customers will rally behind the new service as the company pushes for regulatory changes friendly to its business model.

Until this Wednesday, passengers in South Jersey can get up to five free rides on UberX. The service covers Camden, Gloucester and Burlington counties.