Automated Identification of Fastest Vehicle Paths at Roundabouts

Abstract

The geometric design of a roundabout follows an iterative process that aims to achieve an optimal balance among safety provisions, operational performance, and large vehicle accommodation. The evaluation of safety involves checking the speed consistency along the vehicle paths, which requires identifying the trajectories of the fastest vehicles and the speeds at which they travel. A systematic procedure to identify the fastest vehicle paths for all possible movement types between the approaches of a roundabout using as input data the roundabout geometry and the minimum distance between the vehicle and the roundabout edge is proposed. The determination of the fastest path between an entry and an exit is based on the generation of multiple feasible paths and the final selection of the fastest one. The proposed procedure supports the safety assessment of a roundabout geometric design according to the most relevant international guidelines and can be easily implemented in a heuristic roundabout design procedure. The application of the method to a trial case is presented to demonstrate its performance and applicability.