Comparison of fuzzy-based and AHP methods in sustainability evaluation: a case of traffic pollution-reducing policies

In recent years, the debate concerning the concept of sustainability and sustainable development has received increasing attention with reference to interactions between transport and land-use systems. A multi-dimensional vision of sustainable mobility has been accepted as a reference point for stakeholders and experts; it finds a significant representation in the concept of the “three pillars of sustainability” which examines the idea of sustainability from a three-dimensional perspective: social, economic and environmental. This paper presents a Fuzzy-Based Evaluation Method (F-BEM), which is a useful tool for evaluating the sustainability of alternative transport policies. The structure of the method formalises the concept of the “three pillars of sustainability” by means of a set of indicators as input variables. The method determines an overall fuzzy index of the sustainability of each alternative policy analysed and provides information about the combined dimensions of sustainability (equity, viability and bearableness). In order to analyse the operational applicability and effectiveness of the proposed method, various pollution-reducing policies were evaluated with reference to a case study and compared with the Analytic Hierarchy Process (AHP) method. Interpretation of results yielded useful information about the capacity of the model to be used as an alternative to traditional methods of sustainability evaluation, and also indicated further developments of this research.