Uber faces new legal challenge, at home in San Francisco

It looks like Uber has yet another legal hurdle to surmount, this time on its home turf in San Francisco.

The popular ride-summoning startup, which has recently dealt with regulatory challenges in Washington D.C.,New York, and Chicago, is now being sued in San Francisco by the city's cab drivers, who are claiming unfair business practices.

The fast-growing service, which allows customers to use smartphones to arrange transportation in several U.S. cities, announced last month that in the San Francisco market it was testing out a taxi service option within the Uber app, alongside its existing sedan and SUV service. That debut came the day after Uber quietly ended such taxi service in New York City after running into regulatory resistance.

On Friday, Marin County attorney Gary Oswald filed a class action suit in San Francisco Superior court claiming that "Uber is acting as a taxicab company while sometimes denying this fact in order to avoid all regulations governing taxicab companies," according to the suit (embedded below). Among other compensation, the suit seeks temporary and permanent injunctions preventing Uber from using its "black cars" as taxicabs in direct competition with the "duly licensed" plaintiff class.

"Uber is brazenly violating this statutory scheme without even bothering to offer a pretext for their overtly illegal actions just as they have in New York City, Chicago and elsewhere," Oswald said in a press release. "By ignoring the law, Uber is putting at risk the livelihoods of hardworking men and women who drive safely and follow the rules."

Uber denies the allegations and insists that it is complying with all laws and regulations applicable to its business. "Any claim to the contrary is baseless and motivated by those who seek to deprive the public of this safe and convenient transportation option," Uber's San Francisco-based attorney John Quinn said in a statement. "Uber would rather compete for business on the streets of San Francisco than in the courtroom, but Uber will defend these claims in court and is confident of the outcome."

The new San Francisco offering from Uber lets customers request a taxi via the Uber app on their iOS or Android device. At the end of a customer's ride, the driver inputs the fare appearing on the cab's meter into an Uber iPhone -- along with a 20 percent gratuity and a $1 booking fee -- to determine the final charge, which is then billed to a credit card.

Updated at 12:35 p.m. PT: to include a statement from Uber and more details.