On the evaluation of a public transportation network quality : criteria validation methodology

Abstract

A public transportation network serves in adequate way a population if it evolves in time following the existent social reality. Changes made in order to improve service must be analyzed and evaluated. The introduction of modern technology to validate the fare card allowed a quick access to important, although incomplete, data. A data basis with the validation information can be used to construct an origin-destination (OD) matrix which can be used for a service quality analysis. Here it is presented a computer based methodology to evaluate service quality criteria considering what might be interesting for the user. The quality analysis philosophy is the following. First, on the base of automatically gathered data reconstruct the origin-destination (OD) matrix which contains information concerning the number of passengers traveling between zones of a certain region. The OD matrix is used to calculate some criteria characterizing the transportation network quality, such as traveling times, waiting times at a stop or transport occupation. The reconstructed OD matrix always contains errors, which cause errors in the criteria values evaluation. How significant are these errors? A methodology based on statistical analysis for validating the criteria, i.e. for estimating the criteria robustness, is being implemented at the urban bus transport system of Oporto, STCP, allowing the evaluation of the transportation network quality under a number of criteria and guaranteeing rigorous evaluation.