Uber has shelved its self-driving vehicle program after one of its test vehicles struck and killed a female pedestrian in Tempe, Ariz. The accident marks the first known death of a pedestrian hit by an autonomous vehicle on public roads, reports theNew York Times.

Following the incident, Uber suspended testing of its autonomous cars in Tempe, Pittsburgh, San Francisco, and Toronto.

The deceased woman, who has not yet been publicly identified, was crossing the street outside a designated crosswalk at approximately 10 p.m. on March 18 when the accident occurred, reports USA Today. She died on March 19.

As is standard practice when testing autonomous vehicles, the Uber car was in autonomous drive mode, but there was a human safety driver behind the wheel when it hit the woman, according to reports. There were no passengers in the vehicle.

Uber issued a statement that the company is "fully cooperating with local authorities."

Ironically, proponents of self-driving cars claim the technology can help to greatly reduce the number of traffic-related pedestrian deaths.  The Tempe incident may fuel concerns of activists who believe that the technology that allows the cars to sense their surroundings is not yet safe enough for roll-out on real world roads and highways, reports USA Today.