One of the two SmartShuttles in Sion touched the open tailgate of a parked delivery van between the Place du Midi and Place du Scex on Wednesday, 21 September at 5.40 p.m. Following the incident, in which the van and the SmartShuttle in autonomous driving mode were slightly damaged, PostBus had temporarily suspended testing with both its vehicles. After carefully analysing the accident and what had caused it, PostBus and the vehicle manufacturer Navya have decided to resume testing on Thursday, 6 October 2016. The partners have conducted a thorough investigation into the causes of the collision and taken measures which should prevent such an occurrence in the future. To this end, the technical data of the black box was examined, the various sections of the route were analyzed, what had happened was discussed with the attendants on the shuttle, and the situation leading to the collision was re-enacted at the location.

Distance increased

This is how the accident happened: The SmartShuttle, driving in autonomous mode, had made a slight bend to the left as usual before turning on to the bridge over the Sionne. While doing so, neither the so-called LiDAR sensors nor the attendant correctly recognized the danger posed by the 1.4 metre protruding tailgate at a height of around 2.2 metres, which meant that the vehicle touched the rear right corner of the tailgate. The detailed investigations carried out clearly showed that only a series of events could cause such an incident. Whereas the shuttle easily drove past the first corner of the tailgate, the way the van was parked meant that when turning left, the shuttle touched the rear corner. This was only possible because the "free-floating" obstacle was situated more than 2 metres above the ground. In addition, the attendant on the shuttle did not recognize the situation as being problematic and only initiated an emergency stop immediately after contact with the tailgate.

Increased awareness for safety attendants

Over the last few days, the project heads have conducted various test runs both with the repaired “Tourbillon” shuttle, and with “Valère”, the second shuttle. PostBus and the vehicle supplier Navya have implemented technical and organizational measures in order to resume testing. In particular, the safety distance at bends has been increased in addition to fine-tuning a range of minor technical details. Although this may slow down operation, the vehicles can now react much more sensitively to obstacles and stop more quickly. The six safety attendants – three men and three women – have received additional intensive training from Navya and PostBus. They meet every month to exchange their experiences.

7,000 people transported in three months

The incident of 21 September 2016 was a setback for PostBus and for its testing with autonomous shuttles. The partners are, however, convinced that the technical and operational development can continue. They draw a positive conclusion from the first three test months. The two SmartShuttles “Tourbillon” and “Valère” together have driven more than 1,000 kilometres and transported around 7,000 passengers on more than 800 trips through Sion’s old town. The safety attendants on the shuttles continue to keep precise records and to report any necessary interventions. The most frequent intervention was having to drive around obstacles, such as wrongly parked cars, in manual mode. Sometimes, technical disruptions led to one or two-day interruptions to the service. However, PostBus views this as being part of such an innovation project as the operation of self-driving shuttles has not been running for long following their launch on 23 June 2016. Tests are scheduled to end in October 2017.

At the stops, the safety attendants explain how the autonomous shuttles work to visitors from all over the world. Surveys are regularly conducted among customers. Many of them are initially sceptical about the shuttles, but afterwards most of them are very positive about the ride. Their views do not depend on age: In particular, many passengers over 55 are enthusiastic and want to know exactly when and where the SmartShuttles are in operation. It is also interesting that passengers under 20 get onto the vehicle quite naturally as if it were a conventional Postbus. It’s now hard to imagine the townscape of Sion without yellow Postbus shuttles. They have also become popular objects for selfies.