The U.S. State of California has approved a bill legalizing the operation of driverless cars on state roads and highways.

California Governor Jerry Brown signed the driverless car bill at the headquarters of Google in Mountain View, California, on Tuesday afternoon, local time.

The legislation requires the California Department of Motor Vehicles to draft regulations for autonomous vehicles by January first, 2015.

Driving unmanned cars is already legal in Nevada and Florida. The approval of a self-driving car bill in California, the most populous state and the largest car purchasing state in the U.S., will likely pave the way for opening up the era of driverless cars.