Friends of the first known pedestrian to be killed by a self-driving car have called for Uber to be held accountable as questions mount about how the autonomous technology failed to stop the vehicle from hitting a human in its path.

Two days after an Uber SUV fatally struck the 49-year-old Elaine Herzberg in Tempe, Arizona, while traveling in autonomous mode, friends of the victim have argued that the ride-share company should face consequences and criticized government officials for encouraging car companies to test the vehicles on the state’s public roads.

“This shouldn’t have ever happened,” said Carole Kimmerle, a Mesa resident who said she had been friends with Herzberg for more than 10 years and had previously lived with her. “I think this should be a negligent homicide … and the government should also be held accountable.”

Herzberg’s loved ones said they were still in shock on Tuesday after police announced that the Uber car, an SUV Volvo, was driving roughly 40 miles per hour on its own and did not appear to slow down when it collided with the victim, who was walking her bicycle in front of the car at 10pm on Sunday. There was a human operator in the front seat, but police said the car was in autonomous mode, which meant the radar technology may not have detected the pedestrian or the vehicle did not stop for another reason.

Tempe police said Herzberg was not in a crosswalk when she was hit, though some have argued that the car still should have stopped. Uber said it was temporarily pausing its self-driving operations in Phoenix and other cities, but the company has not commented on the cause of the crash.

As federal investigators have begun their inquiry, local police officials have appeared to cast blame on the victim, saying Uber may not have been at fault, sparking further backlash from the woman’s friends.

“Uber should be shut down for it,” one friend, Deniel Klapthor, told the Guardian. “There has to be a bigger punishment than not allowing them to drive it on the street.”

Kimmerle added, “She was not in anyway unsafe. She rode a bike everywhere. She was very cautious of the laws.”

Herzberg had struggled with homelessness, according to her friends, who said she had recently turned her life around and was in the process of starting a new job.

If her family were to pursue a civil case, attorneys could potentially make a range of negligence claims, said Bryant Walker Smith, an assistant professor at the University of South Carolina and a legal expert on autonomous cars.

Depending on what might have gone wrong, the victim’s family could argue that a number of players were liable, including the car maker, the operator behind the wheel, the manufacturers of various specific technologies, and Uber itself, he said.

“The attorney would want to say to a hypothetical jury, ‘These are really scary systems. They demand the utmost care and responsibility.’ And the lawyer would suggest that’s not the case here,” said Smith.

Ryan Calo, a University of Washington law professor and self-driving expert, predicted the company would try to resolve any case quickly and privately: “Uber will settle this immediately for an undisclosed amount of money.”

The first reported fatal self-driving car crash happened in 2016 when a Tesla on “autopilot” did not detect a white truck in its path. There have since been a series of high-profile incidents involving Teslas, Ubers and other companies, and some have raised concerns that even if self-driving technology is a safer mode of travel, the industry is entering a particularly dangerous phase of development when the vehicles aren’t yet fully autonomous and require humans to intervene.

Arizona has lured self-driving car operators to the state by arguing it has fewer regulations than other jurisdictions – a fact that upset Herzberg’s friends, who said the government should have done more to prevent these kinds of crashes.

“In Tempe, they’re everywhere,” said Jerry Higgins, another friend of Herzberg, who said he keeps his eye on the self-driving cars and said he was struggling to understand how the collision occurred: “Don’t they have a driver in the car that’s supposed to keep stuff like this from happening? … I don’t see how they didn’t work something like this into the programs.”

Herzberg loved to read and write and was always generous and offering to help others even when she was dealing with her own struggles, said Kimmerle.

“She was very loving,” she said. “The world lost a good person.”

• Contact the author: sam.levin@theguardian.com