Using optimization and metaheuristic method to reduce the bus headway (Case study: Qazvin Bus Routes)

One of the most important parameters in assessing the satisfaction of passengers in a bus system is bus frequency or bus headway. In this study, optimization of the public transportation system’s frequency has been investigated, which aims to determine time interval between the next buses for a set of public transport lines determined by their travel plans. Origin-destination demand and restrictions on existing bus fleets should be considered by results. In this way, a model (MILP) was proposed for a pre-existing model which originally formulated as a non-linear two-level formula. The proposed formulation is capable of solving the real optimality of small scale problems using the MILP technique. In order to solve large scale, a metaheuristic method has been proposed that its accuracy is estimated by comparing exact results. Both an exact and approximate approach have been tested using existing cases, thus, the public transportation system of Qazvin has been used as case study. Although its public transport system has 22 lines, an improvement of about 6% was achieved using this model. This shows that, even in small cases, there are improvements in system efficiency. Since the general improvement of Qazvin bus system was not possible after a considerable amount of runtime, an alternative solution approach was proposed in this study. Therefore, a tabu search method has been proposed, which results in a competitive comparison with the exact model.