A Foster City startup has zoomed ahead of its robot-taxi competition: Zoox today received the first approval from the California Public Utilities Commission to offer rides in self-driving cars to the public.

Passengers can start riding in the company's cars, though Zoox must have a trained test driver at the wheel ready to take over.

"This is an important milestone on our pathway to deploying a fully autonomous service," Zoox spokesman Bert Kaufman said today.

Zoox, which has headquarters in Foster City and testing operations in San Francisco, had already obtained a permit from the California Department of Motor Vehicles to test autonomous vehicles on the road, but that type of permit allows companies to carry only employees and contract workers. Those wishing to transport members of the public in self-driving cars need a permit from the state utilities commission, which oversees transportation services.

With the permit in hand, Zoox is on track to offer a robot taxi service in San Francisco in 2020, as it told The Chronicle in September it planned to do. Kaufman would not say when Zoox will start offering rides to members of the public, or how it plans to sign up passengers.

Zoox still needs to apply for separate permits from the utilities commission and the DMV to test its autonomous vehicles while carrying members of the public without a backup driver behind the steering wheel.

Alphabet's self-driving unit Waymo became the first to secure a permit from the DMV for testing fully driverless cars on public roads in California. The company said in October that it would restrict its test vehicles to specific cities in the South Bay, near its Mountain View headquarters. It has been quiet on how soon the cars might roll.

A Waymo spokesman did not respond to a request for comment.

The industry views Zoox, founded by two relative unknowns, as a dark horse compared with larger rivals like Waymo, Uber and Lyft, as well as a rival backed by a major automaker, General Motors' Cruise. Cruise did not respond to a request for comment.

Still, Zoox has raised $800 million and is valued by investors at $3.2 billion. It now has almost 600 employees, some of whom worked at larger firms like Tesla, Apple and Google, according to employees' LinkedIn pages.

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