Uber has grounded its fleet of self-driving cars pending an investigation into the crash of an Uber autonomous vehicle in Arizona, a spokesperson for the car-hailing service said.

No one was seriously injured in the accident which occurred on Friday in Tempe, Arizona, while the vehicle - a Volvo SUV - was in self-driving mode, the company said.

"We are continuing to look into this incident and can confirm we had no backseat passengers in the vehicle," the Uber spokesperson said.

The crash occurred when the other vehicle "failed to yield" while making a left turn, Tempe police spokeswoman Josie Montenegros said.

"The vehicles collided causing the autonomous vehicle to roll onto its side. There were no serious injuries," she said.

Self-driving Uber vehicles always have a driver who can take over the controls at any time.

Ms Montenegro said it was uncertain whether the Uber driver was controlling the vehicle at the time of the collision.

The company grounded its self-driving vehicles in Arizona after the accident, and then followed up yesterday by pulling them off the road in Pittsburgh and San Francisco, the two other locations where it operates self-driving vehicles, the company said.

Advocates of self-driving cars say that they can cut down on deadly traffic crashes by eliminating human error.

But there have been crashes, including a fatality in Florida last May when a truck struck a speeding Tesla that was on autopilot.

An investigation found no safety-related defects with the autopilot system, but concluded that the driver may have had time to avert the crash if he had been paying closer attention.