Transfer-Based Customized Bus Network Design With Holding Control and Heterogeneous Fleet

Customized bus (CB), as an emerging urban shared transportation mode, can provide residents with flexible, high-quality, economical, and efficient transportation services. Most studies assumed that CBs transport passengers directly from their origin to destination without transfer, leading to potential inefficiencies and underutilization of capacity. This article establishes a mixed-integer nonlinear programming model for the CB network design problem that comprehensively considers passenger transfer, heterogeneous fleet, and holding control strategies. The model jointly optimizes routes, timetables (including arrival time and holding time for each vehicle at each station), and passenger-route assignment schemes to meet all the travel demands while simultaneously reducing operational costs. To solve the model, a linearization technique and an improved particle swarm optimization (IPSO) algorithm are, respectively, proposed for exact and near-optimal solutions. To validate the effectiveness and applicability of the proposed method, numerical experiments are conducted on the Sioux Falls network and a large-scale dataset from Beijing, China. The results demonstrate that the IPSO algorithm can effectively provide high-quality solutions compared to the GUROBI solver and benchmark algorithms. Furthermore, incorporating passenger transfers, heterogeneous fleets, and holding control strategies can effectively reduce operational costs and optimize the utilization of transportation resources.