Uber adds San Francisco to self-driving car project

Uber announced on Wednesday that it would extend its testing of autonomous vehicles to San Francisco, the second city in its ambitious autonomous ride-sharing project.

The move comes three months after Uber began testing self-driving cars to move people in Pittsburgh, Pennsylvania, with four vehicles -- along with a driver and technician onboard to deal with any glitches or emergencies.

"We're excited to start operating in our hometown of San Francisco with Volvo XC90s, our first cars built in partnership with a major auto manufacturer," Uber said.

"The promise of self-driving is core to our mission of reliable transportation, everywhere for everyone. While it won't happen overnight, self-driving will be an important part of the future of transportation -- a future we're excited about," Uber added. 

Uber said the San Francisco test would help its engineers get more data to improve its technology, with a climate and traffic conditions which are different than those in Pittsburgh.

Any Uber user in San Francisco may be offered a ride in one of the new vehicles, but will be notified and have an opportunity to decline and choose a human driver.

The launch comes amid growing interest by automakers and technology firms in autonomous cars. The backers of such technology say it can reduce more than 90 per cent of accidents, which come mostly from human error.