Amazon-owned autonomous vehicle company, Zoox, has temporarily halted its driverless testing program for over a week and voluntarily recalled its software due to a crash that occurred in Las Vegas, as reported by the company and filed with federal safety regulators.

On April 8, a collision involving an unoccupied Zoox vehicle and a passenger car led to the company issuing a recall for approximately 270 vehicles equipped with a specific version of its automated driving system. Although the recall affects about 270 vehicles, it does not represent the entirety of Zoox’s fleet, according to the company. The recall was issued as a precautionary measure, as the self-driving software may have been unable to accurately predict the movement of another vehicle, potentially increasing the risk of a crash.

Fortunately, no injuries were reported, and only minor damage was sustained by both vehicles. The incident occurred when a passenger car rapidly approached the lane from a commercial driveway where the purpose-built robotaxi was traveling, as explained by Zoox. The Zoox vehicle, which incorrectly predicted that the passenger car would proceed, slowed down and steered to the right. However, the passenger car came to a stop, yielding to the Zoox robotaxi, and the Zoox vehicle was unable to avoid contact, despite braking hard, according to the company’s blog post.

Zoox confirmed that it paused all driverless testing operations on April 8, the day of the crash, and initiated an internal review. Testing resumed after a software update was implemented across all Zoox vehicles on April 17, as stated in a report submitted to the National Highway Traffic Safety Administration.

The crash and subsequent recall come at a time when Zoox is working towards launching a commercial robotaxi service in Las Vegas. A company spokesperson has confirmed that Zoox still intends to launch this service later in the year.

Zoox has been testing its self-driving system in various vehicles, including retrofitted Toyota Highlanders and custom-built robotaxis without steering wheels or pedals, in multiple cities such as Las Vegas and certain San Francisco neighborhoods. Earlier this year, the company allowed select individuals, including employees and media representatives, to test the service. Additionally, Zoox is conducting tests in Austin, Miami, and Seattle using Highlanders equipped with human safety operators.

This marks the second recall issued by Zoox this year. In March, the company voluntarily recalled 258 vehicles due to issues with its autonomous driving system that could cause unexpected hard braking.

Last year, the National Highway Traffic Safety Administration conducted a preliminary investigation into Zoox after receiving two reports of incidents where motorcyclists collided with the back of Toyota Highlanders equipped with Zoox technology. The investigation found that in both cases, the Zoox vehicles were operating with their autonomous systems engaged.