Bus Size and Headways Optimization Model Considering Elastic Demand

Abstract

This article proposes an optimization model for designing the intervals (headways) and sizes of buses circulating on public transport networks by minimizing the system’s operating and user costs. The proposed model takes into account congestion on the public transport system and works by considering elastic demand, allowing the analysis of the repercussions of modifications made to the operational characteristics of the public transport system on changes in users’ mode of transport. An in-depth sensitivity analysis checks the influence the value of time has on the final model results, and these results are compared with those from a model using inelastic demand. The validity of the proposed model is shown by applying it to the city of Santander, Spain. Finally, the consideration of elastic demand is shown to be beneficial in response to proposed operational changes rather than the assumption of a fixed and known public transport trip matrix.