As the use of the automated shuttle bus (ASB) continues to increase, there is a need for investigating their impact on the safety of vulnerable road users (VRUs) such as pedestrians, bicyclists, and motorcyclists. Studies so far on the automated vehicles and road users focused on detecting pedestrians, communication methods, and prediction of pedestrian’s behavior. The main limitation of these studies was not considering the interaction between the autonomous vehicle and the road user. This research modeled the interaction between the vehicle and the road user with the objective to determine crash risk associated with ASB-VRU interactions and identify the effects of the parameters to improve safety. Computer-based simulations were used to analyze the safety performance of ASBs and its interaction with pedestrians and bicyclists for real-world roadways. The computer simulation enabled exploration of safety-critical cases and consisted of modeling the overall motion and basic decision-making process of the vehicle and pedestrian. Minimum gaps that pedestrians accept during road crossing were obtained from the Matlab simulation model. A finite element simulation model was developed to determine risk injury criteria for both head and chest, if an unavoidable crash were to occur. Using the simulation and field crash data, scenarios were identified that could lead to hazardous situations for pedestrians. The combination of extensive simulations and use case (provided by the industry partner) identified high-risk scenarios and addressed the safety of the VRUs. The crossing, the bus station, and the roundabout were the most challenging type of interactions that autonomous vehicles can have regarding pedestrian’s safety. A risk assessment of ASB-VRU interactions was conducted and recommendations for supporting the ASBs’ safe operation were made. The safety framework for the ASB-VRU interaction was provided to assist transit agencies, developers, and policymakers to make informed decisions and minimize the risk for the road users. Safety is one of the important challenges to a wider adoption of the ASB. By providing objective information and improving safety, this project is expected to contribute to the growth of the ASB industry.
The final report is available.