A growing number of private coaches with blackened windows, upholstered seats and Wi-Fi that shuttle employees of Google, Apple Inc. and Facebook Inc. to Silicon Valley have fueled a debate about inequality in a city where software engineers just out of college can expect to make more than $100,000-a-year while their drivers and other residents who make half that amount are paying $2-a-ride on public buses and struggling to keep up with fast-rising rents.

It's not fair that the city collects only $1 from the shuttle buses for each public bus stop they use, Aaron Peskin, former president of the San Francisco Board of Supervisors and a member of the community group suing the city, said in a statement. He called the contribution from Google, Apple, Genentech Inc. and other companies "a pittance."

"Car pooling and getting additional cars off the street is important, but it doesn't mean you go about it this way, as a giveaway, which is what this program is, without any alternatives considered," Peskin said. "This program was created by the tech industry for the tech industry."