By Mary Papenfuss

SAN FRANCISCO (Reuters) - Activists have sued the city and county of San Francisco over a pilot program giving shuttles run by Google and other private companies access to municipal bus stops, claiming it favors higher-paid technology workers over low-income residents.

The lawsuit, filed in San Francisco Superior Court on Thursday, marks the latest sign of tensions in the Bay Area over the growing income divide, which has been widened by the latest tech industry boom.

Late last year, protesters began to block the commuter buses that ferry employees from San Francisco to the offices of tech companies, including Facebook, Google and Yahoo, south of the city, which they say symbolize the rift being created by abundant tech money.

Under the 18-month pilot program the unmarked, WiFi-equipped buses use San Francisco Municipal transit system stops for a fee of $1 per stop per day and are viewed by many as a symbol of the industry's disconnect from a broader community left behind by the tech boom.

The lawsuit, filed by a coalition of transit and housing activists and a labor union, argues that in addition to displacing lower-income workers, the buses will increase pollution, boost risks to pedestrians and bicyclists and interfere with public transit.

"It's a good thing to transport employees to work on buses, but there is an impact," said Oakland attorney Richard Drury, who's representing the plaintiffs. "We want the city to analyze what that is and mitigate the harm as much as possible."

San Francisco has exempted the project from review under the California Environmental Quality Act, citing guidelines that allow such action for a data-gathering phase of a plan that doesn't create a "major disturbance" to an environmental resource, which the suit charges is a violation of the law.

"There's one set of rules for the tech industry, and another set for the rest of us," complained Chris Daley, political director of SIEU Local Union 1021, a plaintiff in the suit with the Coalition for Fair, Legal and Environmental Transit. The buses tie up traffic and make their way into public bus stops without paying a fair share of the freight, he said.

A spokesman for City Attorney Dennis Herrera said there would be no comment until after the staff had an opportunity to study the complaint.

A city study estimates that 350 private buses account for 35,000 boardings each day at 200 San Francisco sites, many of them MUNI stops, which the vehicles currently are not legally allowed to use.

(Editing by Dan Whitcomb and Ken Wills)

[Image via Agence France-Presse]