Assessing social and distributional impacts of transportation policies for optimizing sustainability

Zusammenfassung

Attempts to integrate sustainability in the decision-making process for transport policies continue to gain momentum. At this point, there is a general consensus on the need to achieve the dual goals of efficiency and equity when implementing transport planning decisions. Therefore, transport planners are usually involved in designing, implementing and evaluating policies that contribute to favour economic development and to accomplish transportation needs of society in a manner consistent with natural laws and human values. In this context, social equity has been gaining importance as a requirement for sustainable development, which comprises social, economic and environmental dimensions with a long-term perspective. However, most social assessments of transport planning decisions remain purely qualitative and often very superficial since, in practice, there is little guidance for its comprehensive analysis. Despite the fact that transportation policies and planning practices often have significant and diverse impacts, there is still only a limited evaluation of the equity implications and the distributional incidence of these policies. As a result, regardless of the widespread implementation of transport policies in many cities and urban areas, few quantitative assessments have been carried out to evaluate whether they meet social needs of the disadvantaged people. Without this kind of analyses, the extent to which they promote social inclusion cannot be determined with certainty. On the basis of these considerations, the overarching objective of this Thesis is to review, assess and evaluate the social impacts of existing transportation policies and their potential equity consequences from the sustainability viewpoint. To that end, the research evaluates the incidence of different real transportation planning decisions on social inclusion —particularly on income distribution— by applying econometric methodologies and statistical techniques such as regression and discrete choice models. Particularly, the research involves analyses on commonly assumed progressive (transport subsidies and transport benefits) and regressive (road pricing) policy alternatives, taking the city of Madrid, the region of New York-New Jersey and the Spanish interurban toll network as case studies. Furthermore, a comprehensive framework on the topic of transport evaluation is provided aimed at understanding the role of social and distributional impacts in exante assessments. The research also gives insight for an alternative weighting scheme to embed social equity issues into the existing appraisal process. Finally, the Thesis yielded some interesting conclusions for both policy-makers and practicing planners with regard to the promotion of more efficient and socially inclusive transport policies.