WASHINGTON (Reuters) - The top U.S. auto safety watchdog said he opposes a “patchwork” of state regulations on driverless cars and promised a “nimble, flexible” approach to writing new rules for self-driving vehicles.

Mark Rosekind, head of the National Highway Traffic Safety Administration, said the agency does not yet have a position on California’s proposal to bar autonomous cars without a person in the driver’s seat ready to take over.

The proposal is opposed by innovators in driverless cars, such as Google, but is consistent with NHTSA’s 2013 guidelines on driverless cars. Transportation Secretary Anthony Foxx has asked the NHTSA to review those guidelines to ensure they do not hold back innovations.

“We need to figure out how to make sure this is not a patchwork (of state regulations),” Rosekind said on the sidelines of an event on drunk driving. “We are pretty deep into looking at our regulatory framework that we currently have.”

“We keep talking nimble, flexible. Two years is like ancient now. That’s being reviewed,” Rosekind said of the 2013 guidance.

Rosekind said NHTSA is talking to state officials in an effort to “have some kind of national approach to this.”

On Wednesday, the California Department of Motor Vehicles proposed state regulations that would require all autonomous cars to have a steering wheel and throttle and brake pedals when operating on California’s public roads citing safety concerns. A licensed driver would need to be in the driver’s seat ready to take over in the event something went wrong.

Rosekind noted that Europe has a “patchwork” approach to driverless vehicle testing that is “problematic.”

NHTSA is reviewing California’s rules, but states have wide authority to set state driving regulations.

Chris Urmson, the director of the Google self-driving project, said California seemed to be shrinking back from its leadership.

“This maintains the same old status quo and falls short on allowing this technology to reach its full potential, while excluding those who need to get around but cannot drive....We can do better,” Urmson said in a statement.

The NHTSA’s 2013 guidance also says a person should be in the driver’s seat ready to take over.

Foxx also wants NHTSA to look at other federal barriers to driverless cars. Rosekind hopes to unveil findings early next year.

Some of Google’s self-driving cars are governed by a federal regulation that limits them to 25 miles per hour. California allows those cars to travel on roads where the speed limit is 35 miles per hour.

“Our regulations don’t line up with what’s actually going on,” Rosekind said.