Consumer Watchdog has called on the National Highway Traffic and Safety Administration (NHTSA) to put the safety of drivers and other vehicles first as it revises its two-year-old policy on self-driving vehicles.

NHTSA last issued guidance on robot cars in 2013, which advised states to limit the vehicles for testing, but not allow them for general use.

"Any new policy from NHTSA must continue to put public safety first," said John Simpson, Consumer Watchdog's Privacy Project director.  "Any robot car must be equipped so a human driver can take control when necessary."

California's autonomous vehicle testing regulations followed NHTSA's 2013 guidance and require a licensed driver behind the steering wheel capable of taking over the test vehicle when necessary.  Ten companies are testing robot cars in California.

On Monday, US Department of Transportation spokeswoman Suzanne Emmerling said Secretary Anthony Foxx ordered NHTSA to update the policy "to reflect today's technology and his sense of urgency to bring innovation to our roads that will make them safer".

One of the most difficult problems still be solved, Consumer Watchdog said, is how robot cars would interact safely with human drivers in other vehicles.

The California Department of Motor Vehicles is expected to issue draft regulations covering the public use of robot cars by the end of the year.  With an expected public workshop, the necessary public hearings and formal approval process, the earliest the regulations would take effect is next autumn.

"The California DMV correctly is focused on getting the regulations correct, rather than rushing them out the door," said Simpson.  "It's imperative that NHTSA also not succumb to corporate pressure to move so fast that our safety on the highways is compromised."

Consumer Watchdog said any robot vehicle must have a steering wheel, brake and accelerator pedals so a licenced human driver can take control.  The policy must require all the safety equipment required on conventional vehicles be required in the robot car.