Sustainable Infrastructure Multi-Criteria Preference Assessment of Alternatives for Early Design

The tradeoffs between the economic, social, and environmental aspects of infrastructures are not easily evident to decision makers and stakeholders in the initial design phase. This lack of insight, often leads to designs that compromise the social and environmental aspects of designs in order to reduce the initial construction costs of infrastructure assets. In addition to the lack of insight, currently available methods for analyzing alternative infrastructure configurations with respect to decision maker preferences: require analysis on a case-by-case (e.g., pairwise) basis; are not appropriate for the initial design phase (e.g., are time-consuming); and are not adaptable to a range of alternative design solutions (e.g., adding and removing alternatives might require a re-ranking from the decision maker). This paper presents a modular preference function development strategy that aims to address these issues, termed Sustainable Infrastructure Multi-Criteria Preference assessment of aLternatives for Early Design (SIMPLE-Design). The proposed strategy develops utility functions (indifference curves) for assessing decision maker preferences with regard to various tradeoffs of alternative design options, and leverages available data to provide decision makers with a consistent frame of reference for assessing alternatives. An illustration presented for a decision support tool using the Simple-Design strategy assesses decision maker preferences for commercial buildings with respect to initial construction costs, building damage and business interruption costs, casualty costs (due to the occurrence of natural hazard events), and CO2 emission costs. The designed decision support tool provides streamlined information to support preference assessment with reasonably low cognitive load. Ten out of the twelve decision support tool users stated that allowing the decision makers to define alternatives of equal utility (value) in a systematic manner, and providing information on the various cost types (decision criteria), are the most essential elements of the assessment strategy. The presented modular preference assessment framework, as well as the decision support tool itself, are generalizable and can be adapted to other infrastructure types. The contribution to the body of knowledge is a holistic preference assessment framework that allows decision makers to make more informed decisions-and designers to better incorporate the preferences of the decision makers-during the early design process.