(Updates with comment from driver's lawyer, information on other lawsuits, drivers' protest)
By Dan Levine and Sarah McBride
SAN FRANCISCO, Jan 27 (Reuters) - The family of a young girl killed by a driver affiliated with fast-growing private transportation service Uber sued the company on Monday, adding to Uber's growing list of legal problems.
On New Year's Eve Sofia Liu, 6, died after she, her younger brother and their mother were hit by a car in a San Francisco cross-walk, according to the lawsuit. At the time of the crash, driver Syed Muzzafar was logged on to the Uber X smartphone app and was available to provide rides, the lawsuit said.
In a statement immediately after the San Francisco crash, Uber said the tragedy did not involve a vehicle "doing a trip on the Uber system," and that Uber "deactivated" the driver's account. The company declined further comment on the incident on Monday.
Uber lets people summon rides at the touch of a smartphone button and has entered more than 60 markets, ranging from its hometown of San Francisco to Berlin and Tokyo.
Leaked financials in December indicated that the company, which began connecting passengers with drivers of vehicles for hire about 3-1/2 years ago, is generating $200 million a year in revenue beyond what it pays to drivers.
But mounting legal troubles and discontent among some drivers match the fast growth. On Monday afternoon, a handful of drivers gathered outside Uber's San Francisco headquarters to protest the company's tipping policy and other issues.
One of the protesters was Douglas O'Connor, an Uber driver and a plaintiff in a proposed class-action lawsuit alleging Uber stiffs its drivers on tips by not allowing customers to add an extra tip onto the all-inclusive fee it charges riders. The suit is currently making its way through federal court in California's northern district.
Other charges dog Uber, including in Chicago, where cab companies allege illegal practices including misleading marketing and unfair competition. They have filed suit in federal court in Illinois. Cabbies in Boston have filed a similar case.
Separately, Uber faces allegations in California state court that it should pay to cover medical costs for a woman who suffered injuries including multiple herniated discs after an Uber driver hit her last year.
The wrongful-death lawsuit filed Monday did not specify an amount of damages sought.
Uber X is a lower-cost version of the transportation service with drivers using everyday vehicles, rather than black town cars. Monday's lawsuit alleges Uber X drivers must respond quickly to a request for service using the company's app, which leads to distracted driving in violation of California laws.
After the San Francisco New Year's Eve crash, Muzzafar was arrested on suspicion of vehicular manslaughter with gross negligence and released on bail. No formal charges have been filed by the county, according to a spokeswoman for the San Francisco district attorney.
Muzzafar is also listed as a defendant in the wrongful death lawsuit.
Graham Archer, an attorney for Muzzafar, said the Uber app was running when the crash occurred but declined to discuss details. Muzzafar is "distraught" over Liu's death, Archer said. "The lawsuit is the expected next step in the process of the family reacting to this tragic accident," Archer said. "From my client's perspective we understand and sympathize."
The case relating to the girl's death in San Francisco Superior Court is Ang Liang Liu et al. vs. Uber Technologies et al., 14-536979. (Reporting by Dan Levine and Sarah McBride; Editing by Cynthia Osterman and Eric Walsh)