FLAGSTAFF, Ariz. — A self-driving Uber SUV struck and killed a pedestrian in suburban Phoenix in the first death involving a fully autonomous test vehicle, prompting the ride-hailing company Monday to suspend all road-testing of such autos in the U.S. and Canada.

Depending on who is found to be at fault, the accident could have far-reaching consequences for the development of self-driving vehicles, which have been billed as potentially safer than cars with humans at the wheel.

The Volvo was in self-driving mode with a human back up operator behind the wheel when a woman walking a bicycle outside a crosswalk in Tempe on Sunday night was hit, police said. Elaine Herzberg, 49, died at a hospital.

Uber suspended its self-driving vehicle testing in the Phoenix area, Pittsburgh, San Francisco and Toronto. The testing has been going on for months as automakers and technology companies compete to be the first with cars that operate on their own.

Uber CEO Dara Khosrowshahi expressed condolences on his Twitter account and said the company is working with local law enforcement on the investigation.

The National Transportation Safety Board and the National Highway Traffic Safety Administration said they are sending teams to investigate.

The crash could be a setback for autonomous vehicle research and lead to stricter regulations from states and the federal government, said Bryant Walker Smith, a University of South Carolina professor who studies the technology.

But Smith said more than 100 people die each day on U.S. roads in crashes of human-driven vehicles.