Publication Detail

Proposed Modifications for Generalizing the TOPSIS Multicriteria Method of Prioritizing Multimodal Mobility Improvements


Research Report

Suggested Citation:
Franklin, Joel P. (1998) Proposed Modifications for Generalizing the TOPSIS Multicriteria Method of Prioritizing Multimodal Mobility Improvements. Institute of Transportation Studies, University of California, Davis, Research Report UCD-ITS-RR-98-11

In developing comprehensive surface transportation plans, state and metropolitan planning agencies have the difficult task of prioritizing multimodal improvement projects within a limited budget. In addition, they must select projects that meet diverse policy goals. Traditionally decision-making agencies have relied upon an economic analysis of costs and benefits, such as a Net Present Value or a Benefit-Cost Ratio, to prioritize mobility improvement projects. However, because not all policy goals can be enumerated in dollar units, a multiple-criterion method that incorporates non-monetizable attributes is more compelling.

One method of prioritizing multimodal mobility improvements using multiple criteria was developed at the University of Washington (UW) for use by the Washington State Department of Transportation (WSDOT). This method employs a prioritization algorithm developed by Hwang & Yoon (1981), known as the Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS). The algorithm assigns a priority to projects based on their Euclidean distances to theoretical best-case and worst-case reference projects, known as "Ideal Projects". The TOPSIS ranking algorithm gave WSDOT programmers the means to incorporate diverse, non-monetizable criteria into a single ranking of projects competing for limited funding. At the same time, the simplicity of the algorithm allowed broad comprehension for all parties involved in the transportation programming process.

By meeting the goal of a generalized TOPSIS method, transportation planning agencies and other public agencies with limited funding will have available an additional tool with which to evaluate and choose alternatives to fund under a limited budget. The use of such a tool affords an agency the benefit of a defensible, systematic method of decision-making that can incorporate different types of evaluation criteria that consider all aspects of the proposed alternatives.

This thesis is organized into six chapters. Chapter 1 provides a background in the transportation programming tasks underway in Oregon and Washington states, and an overview of several project selection methods, both current and theoretical. A review of experiences and emergent issues revolving around two implemented versions of TOPSIS are reviewed in Chapter 2. Special attention is given to the calculations used by the two versions. Chapter 3 presents a discussion of current needs for a future version of TOPSIS, specifically its generalizability and ability to address issues that arose in previous implementations. In Chapter 4, modifications to the previous algorithms are proposed in the form of a revised algorithm, known as TOPSIS-10. Chapter 5 presents an evaluation of the behavior of TOPSIS-10 in the context of earlier versions. Finally, conclusions are drawn in Chapter 6.
Master's Thesis