A vehicle goes by the scene of Sunday's fatality in Tempe, Ariz., where a pedestrian was stuck by an Uber vehicle in autonomous mode. (Chris Carlson/AP)

Debate on the proper role of government in overseeing autonomous cars has sharpened in Washington and around the country after a woman was struck and killed in Arizona by a self-driving Uber vehicle.

A coalition of safety advocates and consumer groups is warning senators — who are considering a bipartisan driverless-vehicle bill — that the 49-year-old pedestrian killed in Tempe on Sunday will probably be the first of many victims of “industry misconduct and government missteps” in the largely unregulated realm.

“The stage is now set for what will essentially be beta-testing on public roads with families as unwitting crash test dummies,” the groups wrote.

But Bill Peduto, mayor of Pittsburgh, where Uber’s self-driving technology unit is headquartered, told a local radio host that “progress and risk walk hand in hand.”

“When we were testing airplanes, there was a risk. When we were testing automobiles, there was risk. When we’re testing inoculation, there’s risk. It’s inevitable that at some point there was going to be a fatality,” the mayor said. “We know, in the long run, these cars will make all cars safer.”

A key question is what will happen with the proposal to set policy on self-driving cars known as the American Vision for Safer Transportation Through Advancement of Revolutionary Technologies (AV START) Act.

The bill, introduced last year by the Senate’s third-ranking GOP leader, John Thune (S.D.), and Gary Peters (D-Mich.), would preempt individual states from regulating “the design, construction, or performance of” autonomous cars and would require carmakers and tech companies to submit an evaluation report to the federal government documenting why their vehicles are safe.

Under current federal policy, such safety letters are voluntary. Waymo, formerly Google’s self-driving car project, was the first to submit such a letter, followed by General Motors. Uber has not, nor have dozens of other companies developing the technology.

The bill would also sharply increase the number of exemptions manufacturers can get from federal motor vehicle safety standards — from a maximum of 2,500 a year to 80,000 annually within several years — as long as they can establish there is a “safety equivalence.” Developers of the technology want to remove steering wheels and make other changes to traditional car designs, but are hindered by rules written in another era.

The House passed comparable legislation on a voice vote in September in a rare bout of widespread bipartisan agreement. This month, Thune said he thought the Senate bill, if it reaches the floor amid competing priorities, could pass with 85 votes.

Thune spokesman Frederick Hill said that prediction stands.

In a statement issued after Elaine Herzberg was killed as she crossed a street mid-block along a darkened thoroughfare, Thune said the tragedy underscores the need for Congress to “update rules, direct manufacturers to address safety requirements, and enhance technical expertise of regulators.”

The National Transportation Safety Board and the Tempe police vehicular crimes unit are among those investigating. Onboard video showed that neither the car, which was packed with sensors, nor a backup driver, who kept looking down, ended up protecting Herzberg as she calmly pushed a bike across the roadway.

Some supporters of the Senate legislation said they thought Herz­berg’s death could complicate discussions about the bill. One Senate aide said opponents are using the incident “as ammunition.”

“The safety advocates have already shaken this thing around. . . . Certainly, the optics don’t look good,” the aide said. But “I don’t think anyone who thinks seriously about this technology and about these vehicles did not know something like this was eventually going to happen, sooner rather than later.”

Days before the fatal crash, five Democratic senators — Dianne Feinstein (Calif.), Kirsten Gillibrand (N.Y.), Edward J. Markey (Mass.), Tom Udall (N.M.) and Richard Blumenthal (Conn.) — signed a joint letter outlining objections to the bill.

Pending the addition of much-needed new safety standards for driverless cars, any “interim framework must provide the same level of safety as current standards,” the letter says. “Self-driving cars should be no more likely to crash than cars currently do, and should provide no less protection to occupants or pedestrians in the event of a crash.”

The senators said exemptions from current standards should be “temporary and reviewable.” They also said there should be a “sunset” on the preemption provision that would keep state hands off driverless regulation. “We are concerned that the bill indefinitely preempts state and local safety regulations even if federal safety standards are never developed,” they wrote.

“It’s all been talked about in terms of theoretical issues up until now,” said Joan Claybrook, a former head of the National Highway Traffic Safety Administration, who wants specific standards such as a “vision test” for the vehicles in the Senate bill. “It’s going to create some momentum and concern.”