A Reliability-based Safest-path-finding Algorithm in Congested Road Networks with Travel Time Uncertainties

Due to traffic demand fluctuation, travel time and accident risk are stochastic in congested road networks. In these situations, many travelers consider not only travel time reliability, but also traffic safety when choosing routes. In this study, we propose a reliability-based safest-path-finding algorithm that takes into account both traffic safety and travel time reliability. The reliability-based safest-path-finding problem is formulated by maximizing the traffic safety index while ensuring that the path travel time satisfies both a specified travel time budget and a given on-time arrival probability. The traffic safety index is defined as the time to avoid a collision with the front vehicle traveling on the same road. An efficient solution algorithm is proposed to solve the formulated problem. A case study using real-world data in Hong Kong validates the proposed algorithm.