AN ANALYTICAL FRAMEWORK FOR SUSTAINABILITY ANALYSIS OF TRANSPORTATION INVESTMENTS ACROSS THE TRIPLE BOTTOM LINE USING A COMMON METRIC

Investments in a more sustainable future require consideration of a comprehensive range of inter-related objectives. Transportation investment decisions affect the entire Triple Bottom Line (TBL) of economy, environment and society. Lacking some common metric, choices among competing objectives remain subject to vagaries of opinion between stakeholders. Establishment of a unifying approach to sustainability assessment is of particular importance to those seeking systematic methods for the restoration of ecological services as they relate to the existing transportation system. Benefit- cost analysis (BCA) has proven to be an effective tool for arriving at clear, transparent analytically based decisions for the optimization of investments in mobility and safety (Gunasekera and Hirschman 2012). Using monetary terms, investment benefits can be adjusted for the time value of money. In this manner, user benefits and project costs over time can be expressed in terms of “present v alue” to facilitate decisions and discussion. A vast body of research is available on the optimization of monetary benefits. However, environmental and social effects as addressed in environmental assessments have typically not been monetized, and are typically not included in BCA fashion. Multi-criteria analysis (MCA) approaches have been used for some time to evaluate projects. In an MCA framework, the actual measurement of indicators need not be in monetary terms, but can be based on the quantitative analysis (through scoring, ranking and weighting) of a wide range of qualitative impact categories and criteria. This approach is currently being applied in a number of emerging sustainability metrics and rating systems, and has done much to encourage and highlight the use of “best practices.” This presentation will review MCA transportation sustainability rating tools and describe an extension of BCA for the quantification and optimization of transportation program and project benefits within a TBL construct and describe a current application of the approach as applied in Minnesota.