Uber's self driving car initiative is on hold after one of its cars was left on its side following a crash.
The incident occurred in Arizona and involved a Volvo SUV operating in self-driving mode. The crash badly damaged another vehicle, however Uber said no one was hurt.
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.
In response, Uber initially pulled its self-driving vehicles from Arizona before taking cars off the road at its other test sites in Pennsylvania and California.
The incident adds to a growing wave of negativity surrounding the brand in recent weeks with president Jeff Jones quitting. His departure followed on from sexual harassment allegations within the company and a slew of senior executive departures.