AKIPRESS.COM - An Uber self-driving car hit and killed a woman crossing the street in Arizona, police said on Monday, marking the first fatality involving an autonomous vehicle and a potential blow to the technology expected to transform transportation.

The ride services company said it was suspending North American tests of its self-driving vehicles, which are currently going on in Arizona, Pittsburgh and Toronto, Reuters reported.

So-called robot cars, when fully developed by companies including Uber, Alphabet Inc and General Motors Co, are expected to drastically cut down on motor vehicle fatalities and create billion-dollar businesses. But Monday’s accident underscored the possible challenges ahead for the promising technology as the cars confront real-world situations involving real people.

U.S. lawmakers have been debating legislation that would speed introduction of self-driving cars.

“This tragic accident underscores why we need to be exceptionally cautious when testing and deploying autonomous vehicle technologies on public roads,” said Democratic Senator Edward Markey, a member of the transportation committee, in a statement.

Elaine Herzberg, 49, was walking her bicycle outside the crosswalk on a four-lane road in the Phoenix suburb of Tempe about 10 p.m. MST Sunday (0400 GMT Monday) when she was struck by the Uber vehicle traveling at about 40 miles per hour (65 km per hour), police said. The Volvo XC90 SUV was in autonomous mode with an operator behind the wheel.

Herzberg later died from her injuries in a hospital, police said.

“The pedestrian was outside of the crosswalk. As soon as she walked into the lane of traffic she was struck,” Tempe Police Sergeant Ronald Elcock told reporters at a news conference.