Handling Uncertainty in Transit Project Evaluation and Rating Process: Comparison Between the Existing FTA Approach and a Fuzzy Inference Approach

A fuzzy inference approach that ranks proposals for major transit projects is proposed, and its performance is compared with the existing approach used by the FTA New Starts Program. The FTA approach uses a rigid mathematical process in which 24 attributes of a proposal are scored initially and then aggregated multiple times to obtain a single overall rating for the proposal. The proposal's funding recommendation is based on this rating. In this approach, a small difference in the initial score can make a significant difference in the final score; that is, the final score is not stable with respect to small perturbations in the initial scores of the attributes. In any evaluation, there is always room for subjective judgment and associated uncertainty to enter when the score of an attribute, the break points on the scoring scale, and the value of the weights of the attributes are determined. The proposed fuzzy inference approach incorporates the fuzziness and approximation associated with the evaluation process and preserves them through the calculation process. In this study, data from the 2012 and 2013 reports of the FTA New Starts Program proposal evaluation were used to compare the FTA approach with the proposed approach. The proposed fuzzy inference approach was found to be robust in dealing with evaluator uncertainty in the initial scores. The final score of this method was found to be more stable than that of the FTA method with respect to small changes in initial values, weights, and break points on the performance scale.