An Evaluation Methodology for the Selection of an Interchange Configuration : Technical Paper

Abstract

The evaluation methodology for selection of an interchange configuration which is presented in this paper is divided into four parts: 1) scrutinize the evaluation criteria to determine which ones are relevant; 2) estimate the initial cost of each reasonable alternative interchange design; 3) develop an Effectiveness Profile for each such alternative design; and 4) compare the initial cost and the Effectiveness Profile for each alternative design and then select an interchange configuration. The selection of pertinent evaluation criteria is fundamental to the evaluation methodology. The criteria chosen should measure differences between the alternative interchange designs. If no such criteria exist, then there is no difference between the alternative designs and the interchange configuration with the lowest initial cost should be selected. The initial cost was used as the cost indicator for each alternative interchange design. The initial cost was selected because it is easily obtainable and does not include some of the uncertainties associated with the calculation of road-user costs. The next step in the evaluation methodology is the development of an Effectiveness Profile for each alternative interchange design. An Effectiveness Profile is a graphical technique which shows each alternative's effectiveness rating for every evaluation criterion. It is based on the cost effectiveness approach of economic analysis and is the accumulation of several cost-effectiveness plots into a single graph. The final step in the evaluation methodology is to analyze the initial cost and the Effectiveness Profile for each alternative interchange configuration. This analysis will provide the decision maker with the necessary information to select an adequate interchange configuration for the given conditions.