A model for the periodic optimization of bus dispatching times

• Published in: Applied Mathematical Modelling Vol. 82; pp. 785 - 801
• Main Author: Gkiotsalitis, K.
• Format: Journal Article
• Language: English
• Published: New York Elsevier Inc 01.06.2020; Elsevier BV
• Subjects: Bus dispatching; Bus regularity; Iterative algorithms; Iterative methods; Operational control; Optimization; Quadratic programming; Rolling horizon optimization; Schedules; Travel demand; Travel time; Bus dispatching; Bus regularity; Rolling horizon optimization; Operational control; Quadratic programming
• ISSN: 0307-904X; 1088-8691; 0307-904X
• DOI: 10.1016/j.apm.2020.02.003

•Novel model for the periodic optimization of bus dispatching times.•Up to 21% improvement in service regularity compared to one-by-one dispatching control.•Solution method with limited computational costs and (almost) negligible optimality gap.•Re-dispatching up to 6 bus trips in a rolling horizon in less than 2 min.•Reproducible numerical experiments. We model the problem of dispatching time control in rolling horizons following a periodic optimization approach reactionary to travel time and passenger demand disturbances. This model provides more flexibility to transport planners allowing them to adjust the bus schedules during the daily operations. We prove that our periodic optimization model is a convex quadratic program, guaranteeing the global optimality of its solution. To reduce the computational burden, we introduce an iterative algorithm that uses gradient approximations to obtain an approximate dispatching solution. The proposed solution method is found to be significantly faster than exact optimization approaches for quadratic programming and maintains an (almost) negligible optimality gap in realistic bus operation scenarios. Finally, we show that our periodic optimization method outperforms myopic methods that adjust the dispatching time of each bus trip in isolation using operational data from bus line 302 in Singapore.