Territorial cohesion impacts of high-speed rail at different planning levels

The assessment of the impacts of high-speed rail (HSR) projects on territorial cohesion has recently emerged as an important issue for transport planners. HSR networks are usually designed to interconnect strong economic centers efficiently. Hence, the greatest improvements in accessibility concentrate near HSR stations, whereas intermediate locations suffer from comparatively lower accessibility benefits. Negative territorial cohesion impacts appear if HSR ultimately results in a more polarized spatial distribution of accessibility levels. There has so far been little research aimed at exploring the implications of the definition of the geographical limits of study area in the measurement of HSR territorial cohesion impacts. In this context, this paper presents a Geographical Information System (GIS)-based methodology which analyzes changes in the territorial distribution of accessibility resulting from HSR investments. These changes are analyzed at different planning levels, in order to assess the sensitivity of territorial cohesion results to scale definition. The methodology is tested by its application to the development of the 670 km of the Galician (northwestern) HSR corridor included in the Spanish PEIT (Strategic Transport and Infrastructure Plan) 2005-2020. Cohesion impacts are assessed at different direct planning levels: regional, corridor and national levels, as well from the perspective of spillover effects. In all cases, the construction of the HSR corridor increases the accessibility values, and results show positive cohesion effects at the national and corridor levels, whereas at the regional level both balancing and polarization effects appear. These differences are mainly due to the location of HSR stations or to the quality of the transport network from the surrounding cities to the station, which determines the territorial distribution of accessibility improvements. Similar results are found from the spillover perspective. (C) 2011 Elsevier Ltd. All rights reserved.