A self-driving bus trial taking place in Vienna, Austria, has been paused after an incident occurred between a pedestrian and one of the vehicles, reports Bloomberg. On Thursday morning a 30-year-old woman collided with the bus, which is operated by the self-driving startup Navya, sustaining minor injuries. The city’s transit authority has paused the trials of the two autonomous buses while it awaits the results of an investigation into the incident.

It’s currently unclear who was at fault for the collision. State broadcaster ORF reported that the bus was moving at about 7.5 miles an hour when it struck the knee of a woman, according to Bloomberg. In a statement given to The Verge, Navya claimed that witnesses had seen the pedestrian wearing headphones and looking at a mobile phone as she crossed the street and “walked against” the side of the bus. Golem reported a similar account from an eyewitness. Navya said the woman suffered “minor scratches” as a result of the incident.

Navya also operates trials in other cities

“Even though this incident ended without too much damage, we take it seriously. We are already analyzing the logs of the incidents in order to shed light on what happened. For this reason, the buses remain in the garage until they are clarified,” Navya said, adding that it intends to release a final report later today.

Regardless of who is at fault, it’s an unfortunate setback for the French startup, which has already run other autonomous bus trials in dozens of cities around the globe. Navya did not immediately confirm the status of its other trials, or whether they have been suspended in the wake of the incident. Vienna’s trial has only been operating since June 6, and includes a professional driver on-board each bus as a backup in case of any problems.

Even though the pedestrian’s injuries were reportedly minor, the incident is likely to be heavily scrutinized by regulators who are wary of safety concerns surrounding the emerging autonomous vehicle industry. Last year the industry was rocked by a fatal collision in Arizona involving an Uber self-driving car, although Uber later resumed its tests that year. A state attorney has since announced that Uber will not be charged with a crime as a result of the incident, which occurred while the backup driver was reportedly watching Hulu.