An incident involving an autonomous bus striking a pedestrian in Vienna is currently being investigated by Austrian authorities.

While the hit only resulted in minor injuries, the city’s transit authorities have temporarily suspended further trials. The vehicle was a Navya SAS shuttle, traveling at 12 km/h (7.5 mph) when it struck a 30-year old woman in her knee, according to state broadcaster ORF.

Vienna has been testing two driverless buses under a program that began last much, with the Austrian Institute of Technology and Siemens mobility also participating in the project, as reported by Autonews Europe.

As of right now, it’s unclear what happened, especially since these projects require a professional drive to be on board whenever these autonomous units are operating in public.

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According to Navya, their Autonom Shuttle model was “specifically designed to meet the needs of an autonomous, driverless vehicle while also optimizing navigation and safety features.”

“With neither a steering wheel nor pedals, Autonom Shuttle uses effective guidance and detection systems that combine various types of advanced technology. Data from Lidar sensors, cameras, GPS RTK, IMU and odometry is merged together and interpreted by deep learning programs.”

Ultimately, it wouldn’t be fair to speculate with regards to what happened in Vienna, especially since we don’t know who was at fault, the pedestrian or the shuttle’s on-board tech (or more specifically, which sensor/program). It’s a good thing though that the vehicle was moving at a very low speed and the woman didn’t sustain any life-threatening injuries.