Uber released a statement on Monday morning that didn't confirm the vehicle's mode:
"Our hearts go out to the victim’s family," the short statement said. "We are fully cooperating with local authorities in their investigation of this incident."
The Uber self-driving car had a backup driver in the driver's seat and no passengers.
The death appears to be the first worldwide from a self-driving vehicle.
The company has temporarily halted operations in Phoenix, Pittsburgh, San Francisco and Toronto, for now ceasing the thrum of gray Uber Volvos that typically take to Tempe streets every day. However, a Waymo self-driving vehicle was seen operating near the collision scene on Monday morning.
Uber is one of several companies testing semi-autonomous vehicles on the roads of Arizona, and the company said it came to the state specifically because of lax rules on the technology created by Governor Doug Ducey.
Tempe police spokesman Sergeant Ronald Elcock said the Uber vehicle, in autonomous mode, was moving northbound on Mill Avenue just south of Curry Road when it hit a woman "walking outside the crosswalk" who had crossed the road from west to east.
"She was transported to a local area hospital where she passed away from her injuries," Elcock said. "Uber is assisting and this is still an active investigation."
Elcock later identified the woman as Elaine Herzberg, 49.
Ducey's office published new requirements for the companies two weeks ago following questions about the vehicles' safety and a previous Uber self-driving collision last year. In that crash, which resulted only in minor injuries, police said the Uber vehicle was not at fault.
Phoenix New Times asked Tempe Police Chief Sylvia Moir and Tempe PD for an interview and information about the safety of Uber's program in late January, but the city ignored the request.
(UPDATE: 1:15 pm — Sergeant Elcock confirmed the victim's name and time of the crash. I've updated the article with that information. Elcock added that the Maricopa County Attorney's Office will "review" the case.There is still no word from Ducey's office on the incident.)
(UPDATE 5 p.m. — Elcock released new details about the incident. Read the follow-up article here.)