Optimization of service frequencies in bus networks with harmony search algorithm: An application on Mandl's test network

Abstract

In developing countries, efforts to increase the efficiency of bus transportation, which is the most common type of urban public transport systems, have been increasing in recent years. Many studies addressing the performance of bus systems focus on approaches to optimizing user and operator benefits. In this study, a bi-level simulation/ optimization model is developed to optimize service frequencies in urban bus networks. At the upper level, a meta-heuristic Harmony Search (HS) optimization technique based model is proposed for solving an objective function that represents operator and user costs. At the lower level, the transit assignment problem, which represents the distribution of demand over the transit network, is solved. In the proposed model, a time-table based transit assignment approach is used for the exact calculation of transfer wait times, and the transit assignment problem is solved using VISUM software based on a logit-based choice model. The developed model has been applied to a test network that is widely used in transit network design studies. The results show that the HS based model can be used effectively to solve the service frequency optimization problem.