Chapter Six - Public Transport Networks

Abstract

This chapter describes the methods now employed for vulnerability analysis of public-transport networks. The main focus of this work is on the railway networks, particularly on urban metro systems. Typological methods are widely applied, using the standard metrics of node degree, characteristic path length, centrality, and network efficiency, but the most advanced studies have gone further, in defining new versions of these metrics that include variables such as passenger flows, origin–destination travel patterns, and generalized travel times. Perhaps serviceability is the most advanced method based on link centrality developed by Cats and Jenelius and their colleagues. This method is applicable to multimodal transit systems and is dynamic, able to handle time-of-day and day-of-week variations, the stochastic nature of transit line operations, and travel demand. Changes in passenger welfare as an impact of service disruption provide a vulnerability criterion for assessment of importance, exposure, and criticality using this method. There is no reported application of an accessibility-based transit network vulnerability analysis, but the development of new accessibility indices, expressly for urban transit systems, can be seen as a precursor to such studies in the near future.