A basic question for the assessment of the fairness of a project financing formula on successive generations is to determine what is the most appropriate method to group the affected individuals over the years. The generational approach in the “Intergenerational Redistributive Effects Model” (IREM) deals with it through the ad-hoc concept of overlapping annual generations. This concept requires establishing the number of years (or timespan) included in the generation and how to incorporate in it those individuals living in years that are not the central one. To do so in a way that reflects the sensitivity of society to the effects of a major transport infrastructure project, specific surveys with a novel approach were designed. The outputs from the survey carried out in Catalonia show evidence suggesting that discount functions should tend to decline at a higher rate in the short term than in the long term. Thus, future impacts of transport investments, both future socio-economic net benefits and financial burdens, should be considered less important than immediate (present) outcomes in the decision-making process. Further, there are reasons to consider that discounting is not neutral to reflect the social interest of large-scale transport projects for the successive generations involved.

Peer Reviewed