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A crash in Tempe, Arizona, on Saturday has led ridesharing company Uber to suspend its self-driving car program. No one was seriously hurt in the incident, but the self-driving Volvo was flipped on its side after another vehicle "failed to yield" appropriately at a left turn.

"There was a person behind the wheel" of the Volvo at the time of the crash, said an Uber representative, and it "is uncertain at this time if they were controlling the vehicle at the time of the collision." The vehicle had two "safety drivers" in its front seats because, as Uber said at its pilot program's rollout, driverless cars "require human intervention in many conditions, including bad weather."

Before the crash, Uber's self-driving cars were being tested in its Arizona, Pittsburgh, and San Francisco markets.