Analysis of mobility impacts of the high speed Rome–Naples rail link using withinday dynamic mode service choice models

The decrease in travel times, the better quality of the supplied services and the improved accessibility are the main factors of success of High Speed Rail links.In this paper, evidence of the impacts of the High Speed Rail line between Rome and Naples in Italy will be provided on the basis of a survey which was carried out in March 2008.A Revealed Preference (RP) survey was undertaken by Trenitalia (the Commercial Division of Italian railways) and three different questionnaires were prepared to be submitted to car users, Intercity train users and High Speed train users. They all have in common questions concerning the socioeconomic characteristics of the users, questions related to the existence of possible time constraints for the trip undertaken and questions concerning previous travel choices.Data from Trenitalia highlighted that the use of car and of Intercity trains had almost remained unchanged during the few years of operation of the High Speed service. However, a generated demand was derived from the use of this High Speed Rail link and this means that the introduction of the High Speed service between Rome and Naples probably had impacts, as excepted, on mobility choices (i.e. increase in trip frequency, new trips never done before, etc.). Data gathered were used first of all to understand this phenomenon and then to estimate a mode choice model to reproduce/forecast modal share. Specifically the choice between car and rail was modelled through a schedule based approach and with a Nested Logit model with the “train” utility function including late and early penalties.

Research highlights
► Revealed Preference survey to analyse Rome-Naples High Speed Rail users’ choice behaviour
► Cities linked by High Speed Rail are transformed into a functional region
► Previous car users leave car in favour of High Speed Rail
► Schedule based approach to model mode choice
► Nested Logit approach: “train” utility function with late and early penalties