On Sunday, a 49 year old woman was struck and killed in Tempe, Arizona by an Uber vehicle that was doing testing of its autonomous mode. Reports from BBC indicate that there was a human monitor behind the wheel, but according to Tempe Police Elaine Herzberg was not using a crosswalk when the Uber car struck her.

Herzberg was taken to a local hospital where she later died. Both the U.S. National Highway Traffic Safety Administration and the National Transportation Safety Board are sending teams to Tempe to investigate exactly what went wrong.

Remarkably, even as Uber rolled out cars to test across several states, including Arizona, California, and Pennsylvania there are no real national safety guidelines regulating these autonomous cars. Vehicles which are using relatively new technology are largely unregulated even as industry heavyweights such as Ford, General Motors, and Elon Musk’s Tesla Corporation tout driverless cars as a safer way to reduce accidents.

However, lobbyist groups such as Consumer Watchdog have been warning of the risks of autonomous cars, and on Monday called for an immediate suspension of autonomous car tests, saying that this accident is “[a] tragedy we have been fighting years to prevent… We hope our calls for real regulation of driverless cars will be taken seriously by Silicon Valley and the Trump Administration.”

Uber previously stopped its driverless car program in 2016 after an accident in Arizona left a Volvo SUV on its side following. However, the self-driving car tests were later resumed.

Tempe Mayor Mark Mitchell praised Uber’s decision to suspend the self driving program as “responsible” before assuring the public that both city leadership and the Tempe Police Department will be pursuing all leads in the pursuit of safety.