Ride-hailing app Uber has had its self-driving car testing program in Arizona suspended after the death of Elaine Herzberg, a pedestrian who was struck and killed by one of the company’s driverless cars earlier this month.

Arizona’s governor Doug Ducey wrote to Uber’s chief executive Dara Khosrowshahi and said that public safety should be a top priority, and that “[t]he incident that took place… is an unquestionable failure to comply with this expectation”.

He added:

In the best interests of the people of my state, I have directed the Arizona Department of Transportation to suspend Uber’s ability to test and operate autonomous vehicles on Arizona’s public roadways.

The decision is thought to be a significant setback for Uber with with about half of the company’s 200 self-driving cars and a staff of hundreds based in Arizona.

Read more: A history of self-driving car crashes

The company had already been forced to move to Arizona after California regulators kicked Uber’s self-driving fleet out of San Francisco for not having the proper permits.

In a response to the letter, an Uber spokesman Told CNN it had already pulled all its autonomous vehicles from the roads following the accident.

Uber said:

We proactively suspended self-driving operations in all cities immediately following the tragic incident last week. We continue to help investigators in any way we can, and we’ll keep a dialogue open with the governor’s office to address any concerns they have.

This is unlikely to be the end of the road for self-driving cars.

A recent study by non-profit organisation Rand Corporation concluded that self-driving cars that perform just 10% better than human drivers would save thousands of lives.

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Following the collision the chief of the Tempe Police, Sylvia Moir said the technology was likely not at fault for the crash:

I suspect preliminarily it appears that the Uber would likely not be at fault in this accident.

The Tempe police released video footage of the incident.

After the collision the car continued travelling at 38 miles per hour, according to the Tempe police chief Sylvia Moir. The speed limit where the accident occurred is 35 miles per hour.