Model in Consideration of Similarity and Its Application

Based on Hiroshima NTS (New Transit System) SP data, this paper build a model to estimate and forecast shares of travel modes when part of the alternatives set is not available. The IIA property of MNL model is testified not holding, continuous utilization of that model will generate bias. So, a PCL (Paired Combinatorial Logit) model in consideration of similarity between choice alternatives is applied to relax the IIA property. The difference between MNL and PCL model is compared and analyzed, showing the significance of introducing similarity parameter between alternatives. This paper also presents a method to calculate shares of travel modes with similarity parameter of PCL model when lacking some of alternatives, which result is satisfying.