Measuring regional cohesion effects of large-scale transport infrastructure investments - an accessibility approach

Accessibility gains arising from transport infrastructure improvements are one of the key elements boosting a complex process involving transport, land use and regional development effects. The inclusion of the wider socio-economic effects stemming from large-scale transport infrastructure investments is uneven among national evaluation procedures, and there is no commonly accepted methodology to measure them. In addition, there are other effects which do not take into account the overall change in the value of a specific variable, -normally GDP or employment-, but only the changes in its spatial distribution. These distributive effects, related to spatial equity issues, are increasingly included as a policy objective in most infrastructure Master Plans. More over, at a European level, economic and social cohesion is considered among the priority objectives in the enlarged EU. However, the inclusion of cohesion effects in national assessment methodologies is quite limited. If cohesion issues are not taken into account, new infrastructure schemes may induce spatial polarising effects, as more profitable projects are usually the ones which interconnect central regions, at the expense of the relative position of peripheral regions. Moreover, each transport mode has its special features which make it more inclined towards cohesion or polarising effects. In this sense, recent studies at a European level on the impacts of RTE-T show that HSR lines seem to have rather polarising effects, while new road schemes seem to have slight cohesion effects. In this context, activity-based accessibility indicators can be used as a proxy to measure these distributive effects. Changes in the relative positions of the regions in terms of accessibility provide an estimate to test if the Master Plan increases or reduces disparities among regions- i.e. reduces or increases cohesion, respectively. The paper analyses these issues measuring the changes in accessibility stemming from the implementation of different high-capacity road and HSR schemes in Spain. Results show a slight cohesion effect after the implementation of the high-capacity road network, along with a polarising effect arising from the implementation of new HSR lines, in line with the results included in recent European- level studies. The paper is based on the work being carried out for the author’s Ph.D. Dissertation, titled: “Assessment of Transport Infrastructure Plans: a strategic approach integrating environmental, economic and spatial equity aspects”.