Design of Zonal Express Bus Service Incorporating Service Area Selection and Vehicle Route Optimization

Abstract

Zonal express is an operational strategy for express bus service that directly connects origin and destination zones while skipping intermediate stations. Zonal express is regarded as one of the solutions that allow the public transportation system to operate efficiently. This study proposes an optimal zonal express strategy incorporating both service area selection and vehicle route optimization. Specifically, the efficiency of public transportation services of origin-destination (OD) pairs is evaluated to select service areas using data envelopment analysis. Then, 19 OD pairs with low-efficiency scores are selected as service areas. With the selected OD pairs, bus routes and the number of vehicles are optimized by a genetic algorithm-based vehicle routing problem. The objective of the proposed strategy is to maximize efficiency such as passengers’ travel times considering their mode choice behavior. The proposed strategy is applied to the transit network in Seoul, and the results show that the zonal express service could improve the efficiency score of OD pairs significantly. Specifically, 19 of 782 OD pairs are selected as service areas that had a low-efficiency score, and route optimization is performed on selected OD pairs. The result shows that the efficiency score was improved from 0.19 to 0.32 by introducing the zonal express buses. This result implies that the integration of service area selection and route optimization leads to effective and efficient route design.

Keywords: Transit route network design problem, Bus rapid transit, Data Envelopment Analysis, vehicle routing problem, Smart Card Data