Optimizing Headways for Mass Rapid Transit Services

Mass rapid transit (MRT) operators need to balance the total system costs with the level of service. The primary service of MRT systems is to provide cost-efficient mobility. Governments are responsible for establishing and regulating minimum standards to ensure that the MRT service indicators meet a specific level. Thus, approaches to optimizing MRT system service frequencies are critical concerns for MRT system operators. Previous studies on MRT operations have focused primarily on delays, energy conservation, route design, and general system operations. Conversely, few studies have focused on optimizing headway problems. This study adopts a mathematical programming method to develop a headway-oriented model for the Kaohsiung MRT (KMRT) system aiming to minimize system costs while maintaining an acceptable level of train services. The developed model systematically adjusts train headways based on time-series passengers’ spatio-temporal distribution data. A numerical case study and sensitivity analysis were conducted to test the feasibility and effectiveness of the proposed models and solution algorithms. The proposed model framework provided the KMRT operator with a flexible tool to evaluate the effects of service frequency on both operating cost and passengers’ waiting cost, which facilitates the operator to prepare a cost-efficient train service plan.