Uber has pulled its self-driving cars from the roads after an accident which left one of the vehicles on its side. Pictures posted online showed the car on its right side on an Arizona street, next to another badly damaged vehicle. The car - a Volvo SUV - was in self-driving mode at the time of the crash, on Friday, Uber said. A spokeswoman for the police in Tempe, Arizona said the accident occurred when another vehicle "failed to yield" to the Uber car at a left turn. "There was a person behind the wheel. It is uncertain at this time if they were controlling the vehicle at the time of the collision," spokeswoman Josie Montenegro said.