Effects of high-speed rail on regional accessibility

A high-speed rail (HSR) system, which can be developed either by building a new segregated line or upgrading an existing line according to a given set of operational standards, is considered as a competitive solution to improve the accessibility of main destinations. Scientific literature has reported limited contributions regarding the impacts of such infrastructures on the regional systematic mobility and their negative effects on locations excluded from the service. To fill this gap, this paper proposes a method for assessing the implications of regional accessibility on work and study trips, by comparing the two HSR options mentioned above (new segregated or upgraded existing lines). Instead of considering static indicators (e.g., population), the number of train commuters and the variation in travel times for each of the local employment systems crossed by the railway are used as input data. This method is then applied to analyse the territories located along the Venice-Trieste line (in the north-eastern part of Italy) that are characterised by several medium-sized municipalities and crossed by two TEN-T lines. An upgrade of the existing line rather than the construction of a segregated HSR is preferable for local commuters in terms of average travel times and social equity, also considering the expected construction costs. These results complement traditional medium- and long-distance market analyses and may be useful for policymakers to define the most appropriate territorial strategies for the development of specific TEN-T stretches.