Google and other supporters of the legislation, Senate Bill 1298, say robot-controlled cars could drive more safely and efficiently than people, whose errors are responsible for a high percentage of crashes.

Nevada enacted similar legislation last year, and the state recently issued to Google that state's first license to test autonomous vehicles, according to a legislative analysis.

Sen. Alex Padilla, the Southern California Democrat, who authored the legislation, Senate Bill 1298, called it a "dream bill," saying it will save lives, create jobs, ease congestion and reduce emissions.

Opponents of the bill included the Alliance of Automobile Manufacturers and Consumer Watchdog. Automakers have raised liability concerns, while Consumer Watchdog argued Google's driverless cars should not be allowed on California roads until privacy protections are in place.

The legislation requires the Department of Motor Vehicles to adopt regulations related to the technology by Jan. 1, 2015.

Brown, famous for his blue Plymouth sedan when he was governor before, rode in the front passenger seat for a test drive today of a robot-controlled Toyota Prius.

"Only way to go, guys," he told reporters.

Later, he was asked to whom a traffic ticket would be issued in the event a self-driving car ran a red light.

"Whoever owns the car, I would think," Brown said. "But we'll work that out. That's going to be the easiest problem to work out."

Brin stepped in with a more certain answer.

"Self-driving cars," he said, "do not run red lights."