An improvement of a fuzzy three-level model to evaluating transport systems sustainability considering decision-maker's attitude

The concept of sustainable transport has been widely debated in recent years, given its close links with that of sustainable development, by which it can acquire significance. This paper proposes a fuzzy theory-based methodological approach that leads to the definition of a summary indicator of sustainability, that can be used to evaluate the sustainability of a given action plan for transportation and land-use systems. This approach, formalising the “three pillars of sustainability” concept with the theory of fuzzy systems, has the capability to deal with non-homogeneous indicators, maintaining the uncertainty associated with their evaluation and the interrelation between the overlapping dimensions of sustainability. The paper describes the architecture of the proposed model, paying particular attention to the representation of the indicators using fuzzy sets and to the differences with the previous structure of the model.