The Impacts of High-Speed Rail Development on Territorial Cohesion: A Method with Two Case Studies in Italy

In the last decade, the concept of ‘cohesion’ has become increasingly important to study the distributional effects of infrastructure investment between different population groups, i.e., social cohesion, or between different zones inside a study area, i.e., territorial cohesion. Nevertheless, despite a growing interest, in the literature there is still a lack of consolidated methodologies and guidelines to assess the impacts on cohesion of transport infrastructure. In the attempt to bridge up this gap, this paper proposes a method based on the estimation of zonal accessibility variations as proxy for the effectiveness of the investment, and on statistical indices estimating accessibility dispersion as a proxy for the territorial cohesion. Two case studies are presented: the completion of the High-Speed Rail (HSR) line between Turin–Venice (Northern-Italy) and the construction of the new HSR line between Naples and Bari (Southern-Italy). The application shows that the investment in the more industrialized and densely populated areas of North Italy turns out to be more effective in terms of accessibility improvement than in less developed Southern ones. However, while the former increases inequalities in terms of accessibility and risks to amplify the gap between North and South of the Country, the latter (Naples–Bari) tends to reduce such disparities.