WASHINGTON (BLOOMBERG) - A video recording from the Uber self-driving car that struck and killed a woman on Sunday (March 18) shows that she moved in front of it suddenly, a factor that investigators are likely to focus on as they assess the performance of the technology in the first pedestrian fatality involving an autonomous vehicle.

The Uber had a forward-facing video recorder, which showed the woman was walking a bike at about 10pm and came from a darkened centre median into traffic and "it's very clear it would have been difficult to avoid this collision in any kind of mode," Tempe, Arizona, police chief Sylvia Moir told the San Francisco Chronicle.

"The driver said it was like a flash, the person walked out in front of them," Moir said, referring to the back-up driver who was behind the wheel but not operating the vehicle. "His first alert to the collision was the sound of the collision."

The chief's account raises new questions in the investigation that holds importance to the future of the burgeoning autonomous vehicle industry. Uber Technologies halted autonomous vehicle tests in the wake of the accident.

It's too soon to draw any conclusions from the preliminary information that has emerged, said Brian Walker Smith, a law professor at the University of South Carolina who has studied autonomous vehicle liability.

"It's possible that Uber's automated driving system did not detect the pedestrian, did not classify her as a pedestrian, or did not predict her departure from the median," Smith said in an email.

"I don't know whether these steps occurred too late to prevent or lessen the collision or whether they never occurred at all, but the lack of braking or swerving whatsoever is alarming and suggests that the system never anticipated the collision."

Police later said in a statement that the department would defer to county prosecutors on whether to bring charges, but didn't dispute any of the information released by Moir.

In a news conference on Monday, Tempe police Sergeant Roland Elcock said local authorities had not come to any conclusions about who is at fault.

Decisions on any possible charges will be made by the Maricopa County Attorney's office.

Neither the victim nor the backup driver showed any signs of impairment.

The victim, Elaine Herzberg, 49, was walking her bike outside of the crosswalk. The car was most likely going about 38 mph (61 kph), Moir said.

The department has no plans to release footage while the investigation is under way.

The department expects to give a further update later today.