FLAGSTAFF, Ariz. (CBSNewYork/AP) — Ride sharing giant Uber is putting the brakes on a fleet of self-driving cars in Arizona after a pedestrian was hit and killed.

Elaine Herzberg, 49, was crossing a street in Tempe Sunday night when the sports utility vehicle hit her.

“As soon as she walked into a lane of traffic, she was struck by the vehicle,” Tempe Police Sgt. Ryan Elcock said.

Authorities say Herzberg wasn’t in the crosswalk. The SUV was in self-driving mode, but officials say there was a person behind the wheel.

Uber announced it will suspend its self-driving program while the crash is being investigated.

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 human drivers.

The testing has been going on for months as automakers and technology companies compete to be the first with the technology.

A spokesperson told CBS2: “Public safety is our number one priority and we will of course review the findings of the NTSB’s investigation into the tragic crash in Arizona.”

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

The federal government has voluntary guidelines for companies that want to test autonomous vehicles, leaving much of the regulation up to states. In New York, Governor Andrew Cuomo’s office confirmed people are navigating autonomous vehicles in Lower Manhattan for the purpose of testing the car’s GPS system.

But Transportation Secretary Elaine Chao also has said technology and automobile companies need to allay public fears of self-driving vehicles, citing a poll showing that 78 percent of people fear riding in autonomous vehicles.

“This is the kind of technology that only gets better through experience,” NYU Stern School of Business Professor Arun Sundararajan told CBS2’s Lisa Rozner. “These cars have to drive millions of miles.”

Sundararajan said New York is one of the biggest markets because its spending power.

“This is not a place where you want to own a car so definitely billions if not tens of billions of dollars of market opportunity.”

The number of states considering legislation related to autonomous vehicles gradually has increased each year, according to the National Conference of State Legislatures. In 2017 alone, 33 states introduced legislation.

California is among those that require manufacturers to report any incidents to the motor vehicle department during the testing phase. As of early March, the agency received 59 such reports.

Last year, Cuomo inked a deal with General Motors to test self-driving cars on designated streets in New York City.

Paperwork with the Department of Buildings shows GM Cruise, a driverless car company, plans to lease space at 250 Hudson Street in TriBeCa. The company didn’t reply to CBS2’s request for comment.

(© Copyright 2017 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)