Uber has suspended testing of its autonomous fleet in Arizona after one Volvo XC90 tester was involved in a collision in the city of Tempe.

At approximately 6:25 pm on Friday, local police were called to the crash where one of Uber’s XC90 prototypes was hit by another vehicle that failed to yield.

Uber has confirmed that the vehicle was in self-driving mode at the time and that a driver was behind the wheel but the Tempe Police Department confirmed that the other vehicle as at fault for the crash.

The impact was strong enough to flip the Uber on its side but neither driver was harmed in the crash. There were also no backseat passengers in the Uber, Azcentral reports.

While the Uber wasn’t at fault, this incident is just the latest in a spate of setbacks for the self-driving program. In December, the company’s fleet was famously kicked off the streets of California after the ride-hailing service failed to get a permit to test the vehicles on public roads. Not dissuaded, the company soon moved its fleet to Arizona and received immediate support from Governor Doug Ducey.