The company appears to be backing down from the fight, promising to relaunch the cars elsewhere.

Uber appears to have backed down from its showdown with the California Department of Motor Vehicles after the agency nullified registrations for the company's fleet of self-driving cars.After at least one of the modified Volvo XC90 crossovers was caught on video running a red light, state officials claimed Uber never received the proper permit for operating a fleet of prototype autonomous vehicles.

"We have stopped our self-driving pilot in California as the DMV has revoked the registrations for our self-driving cars," a spokesperson confirmed in a statement posted by NPR. "We're now looking at where we can redeploy these cars but remain 100 percent committed to California and will be redoubling our efforts to develop workable statewide rules."

The agency is said to have killed the registrations because the cars were allegedly operating without being properly classified as test vehicles. Uber has argued that it does not need a permit, because the cars are not quite ready to operate without a human driver behind the wheel to take over at all times. The law defines a subject vehicle as one equipped with technology that can drive "without the active physical control or monitoring" of a human.

"It's hard to understand why the DMV would seek to require self-driving Ubers to get permits when it accepts that Tesla's autopilot technology does not need them," the company argued in a blog post last week. "We cannot in good conscience sign up for regulation for something we are not doing."

The state has welcomed Uber to relaunch its autonomous testing program in the state ... after it applies for the permits "like everybody else." The company would then be required to submit reports for each accident involving the vehicles and any incidents in which the human driver disengages the system while underway.