Cost-benefit analysis (CBA) has been traditionally applied to the evaluation of transport projects, such as new roads and high-speed rail links. CBA is considered a sound evaluation method but it has important limitations. The emphasis on monetary assessment tends to reduce the range of effects to be taken into account in the analysis. Due to the complexity of the situations associated with transport, multiple criteria decision analysis (MCDA) has been increasingly used for supporting the decision-making process. MCDA can be divided into three main phases: structuring the decision situation, evaluation of alternatives and recommendation for the most suitable alternative (or alternatives). Although they are interacting phases, structuring precedes and prepares the evaluation and recommendation phases. It is that part of the decision-making process in which an analyst or facilitator helps an individual or group think about and understand a situation which requires a decision. Practitioners and academics point out that greater attention needs to be paid to structuring in MCDA, recognizing that if structuring is improved the quality of the decision outcome will be better. This paper aims at emphasizing the importance of structuring and showing that it can provide a comprehensive and rich support to decision processes related to transport projects. Structuring is illustrated by an example on the high-capacity rail system planned for the city of Curitiba, Brazil. After a short description of the project, the effects taken into account in CBA are presented and analysed. Some possible structuring elements of this decision situation are proposed and compared with the effects computed in CBA. The purpose is to show how the various effects of the project (e.g. technical, economic and environmental ones) can be explicitly considered and integrated by means of a multi-criteria decision aiding approach. For the covering abstract please see ITRD E135207.
Abstract