But the advocacy group Consumer Watchdog slammed the new rules, claiming autonomous cars have not yet been proven safe enough to be deployed without a human backup driver.
"It will be just like playing a video game, except lives will be at stake," said the group's director John Simpson.
Fifty companies already have permits to do some sort of testing in California, a prime proving ground given its size as the most populous state, its clout as the nation's biggest car market and its longtime role as a cultural trendsetter.
The vehicles will no longer need to have drivers inside during tests, but people will still be in charge. Under the regulations, driverless cars being tested on public roads must have a remote operator monitoring at all times, ready to take over as needed. The remote operator must also be able to communicate with police as well as any passengers in the event of an accident.
Law enforcement must provide permission to test on local roads and be provided with routes the cars will take.
Manufacturers can apply for permits allowing driverless testing when the regulations go into effect April 2.
The rules written by California's Department of Motor Vehicles and approved by the state's Office of Administrative Law also create the framework under which consumers can eventually buy driverless cars.
Department of Motor Vehicles director Jean Shiomoto said it's a big boost for regulations in the works for years and that "safety is our top concern".
Major automakers like Mercedes, BMW, Ford, Nissan and Volvo have all said it will likely be at least 2020 before their driverless vehicles are available, and even then, they could be confined to ride-hailing fleets and other shared applications.
Tesla said last year that the cars it's making have the hardware they need for full self-driving. The company is still testing the software and won't make it available to owners without regulatory approval.
Industry leader Waymo, Google's self-driving car spinoff, is not commenting on its rollout schedule.
The California regulations do not include testing and deployment of autonomous trucks and other commercial vehicles.
- AP