SAN FRANCISCO — California Governor Jerry Brown on Tuesday signed a bill clearing the way for self-driving cars to jockey with human-operated vehicles to test the technology on the state's roads.

"Autonomous vehicles are another example of how California's technological leadership is turning today's science fiction into tomorrow's reality," Brown said during a signing ceremony at the Google campus in Mountain View.

"This law will allow California's pioneering engineers to safely test and implement this amazing new technology."

The legislation backed by state senator Alex Padilla lets driverless cars be operated on public roads for testing purposes as long as licensed drivers are behind the wheels to take over if needed.

Development of a self-driving car is one of the projects of a special Google research team headed by company co-founder Sergey Brin.

Brown, Brin and Padilla took a ride in a Google self-driving car before the governor signed the bill into law.

"It obviously seems the stuff of science fiction," Brin said.

"It is a fascinating area to work on but it really has the power to change people's lives, which is why I am really excited about it."