Though not at fault, the Uber vehicle was struck and rolled over.

Uber is suspending its self-driving pilot programs after an collision involving one of its autonomous Volvos in Arizona yesterday.

The accident in Tempe, Arizona occurred Friday when a driver failed to yield, striking the Uber Volvo and rolling it onto its side. The vehicle contained no customers, but did have one Uber "driver," an individual who monitors the autonomous vehicle and can take over if required, in the driver's seat. No injuries were reported, and Uber has confirmed that the Volvo was indeed in self-driving mode at the time of the collision.

While police say the Uber car was obeying traffic laws and that the human-guided car was at fault, the incident does raise the question of whether a human driver would have been able to react in a way the autonomous vehicle wasn't programmed to.

In response to the incident, Uber has halted its autonomous car testing program in Arizona, which began February 21, as well as its testing program in Pittsburgh, Pennsylvania, as the company investigates the crash.