Approaches To Weighting Within Transportation Infrastructure Sustainability Assessment

Sustainability assessment systems are increasingly being used as tools to encourage more sustainable practices in the provision of civil infrastructure. In several cases, agencies have developed unique sustainability assessment systems, or adopted modified versions of sustainability assessment systems currently available for a wider market. In any case, the nature of sustainability as a multi-criteria problem requires that preferences must be expressed in order to determine optimal outcomes for more sustainable decision making. These preferences are typically expressed in terms of weights applied to the various criteria in sustainability assessment systems, and the techniques used to derive these weights, as well as how the weights are applied, varies across the many different systems. In this paper, the authors review how weighting is typically included in sustainability assessment systems and make recommendations about how some of the incongruities between the various systems can be understood. Furthermore, the authors present the results from a pilot study which was conducted using an online survey system, and then use the results to make recommendations regarding future surveys designed to elicit weights from such a group.