The development of self-driving cars has hit a bump in the road, after US authorities said they won't be allowed to hit the roads without a driver present.
Regulators in California, where the majority of research and testing of autonomous vehicles is centred, said there needs to be a driver present in case the technology fails.
Google is the best known tester of autonomous vehicles, and has clocked up more than one million miles of testing on the roads of Mountain View in San Francisco, where they have become a familiar site. The company will spin out the research unit into a fully fledged company next year, according to reports.
Apple's secretive step into self-driving vehicles is also forging ahead. The Cupertino-headquartered firm has been eyeing up locations to conduct private tests.
This week, Ford said it will begin testing driverless vehicles on the streets of California next year. The car maker's research into the technology is located in Silicon Valley.
The Department of Motor Vehicles (DMV), which is responsible for regulating the cars, also said the technology needs more testing before going on sale to the public, and that consumers needed training programmes to operate them.
The new proposals will be consulted on and a decision made next year.