Rail versus bus local public transport services: a social cost comparison methodology

In the last years, several Italian legislative interventions concerning the local public transport (LPT) sector aimed at inducing Local Authorities to re-programming the current services by changing the existing transport modes in favor of less expensive ones, while preserving passengers mobility. Indeed, for some local railway routes the existing level demand and its characteristics (e.g. distribution along the day) would justify a switch from rail to bus mode, when the latter are proved to be less expensive in providing comparable services. We propose a methodology to compare the social economic costs associated with the bus and the rail modes in Italy that can represent a simple and effective tool to support the Italian local policy makers in re-programming the LPT services while using more efficiently the (scarce) financial public funds. The comparison is carried out by considering a given level of exogenous demand (e.g. externally fixed), not influenced by the activated transport mode. Differences in the offered level of services are taken into account through estimation of the users cost in terms of in-vehicle trip time. The social economic costs include service production costs, infrastructure usage costs and externalities impacts (e.g. air pollution, congestion, noise). The investment costs for rail and road infrastructures construction are assumed to be sunk, while the generated infrastructure usage costs (increasing maintenance and operations) are included in the analysis. Finally, the proposed methodology is finally applied to an Italian real case.