Measuring Regional Cohesion Effects of Large-scale Transport Infrastructure Investments: An Accessibility Approach

Abstract

Transport infrastructure is considered one of the main policy instruments to achieve the cohesion goal, although the inclusion of cohesion effects in assessment methodologies is scarce and uneven. Although most cohesion studies are constrained to the analysis of regional disparities in economic indicators, this approach can be broadened to include other regional performance indicators. One of these indicators could be accessibility measures, from the point of view that accessibility, representing a competitive advantage of locations, constitutes a “desirable good” closely related to the welfare of each region. This paper suggests using changes in the spatial distribution of accessibility as a proxy to assess regional cohesion effects of transport infrastructure investments. However, as the conclusions taken depend heavily on the formulation of the accessibility measure, we recommend computing a set of accessibility indicators and analysing their results in a complementary way. The proposed methodology is tested by assessing regional cohesion effects of the large-scale road and rail transport infrastructure investments carried out in Spain in the period 1992–2004. The results obtained show that cohesion has improved for the road mode, while regional disparities have increased for the rail mode. This paper identifies the main factors driving this final cohesion effect and explores the strengths and weaknesses of the different accessibility indicators that were considered. The approach suggested in this paper has the potential to be applied in transport planning processes, and may eventually complement existing strategic assessment methodologies.

Acknowledgments

Support from Spanish Ministry of Public Works (Transport Research Aids) and the Ministry of Education and Science (Research Project TRA2004-04355/MODAL); as well as comments by José Luis Romero and three anonymous referees are gratefully acknowledged.

Notes

1. National and regional cohesion has frequently been defined in terms of their parity in gross domestic product (GDP) per capita and unemployment levels.

2. At the level of common usage, the level of overlap between those three concepts makes problematic any attempt to differentiate those words in isolation, as justified in Hay (1995).

3. Nomenclature of Territorial Units for Statistics, defining statistical regions for Europe.

4. Their detailed formulation and a comprehensive review on inequality measurement can be found in Cowell (1995).

5. These spatial contrasts appear clearly reflected in the resulting accessibility maps corresponding to 1992 and 2004 situations (which are not possible to include here for space reasons), and are coherent with previous research results (see e.g. Gutiérrez & Monzón, 1998).

6. The magnitude of the variation in the inequality indices obtained for each accessibility indicator is influenced not only by the characteristics of the sections built in the period 1992–2004, but also by the formulation of the corresponding accessibility indicator, as some of them are more sensitive to changes in the infrastructure network than others.