Multiple Choice Models in Transport Assessment

摘要

The use of choice models is widespread in transport studies. A review of existing choice models includes a critical description of multinomial logit, structured logit, and multinomial probit models. It is concluded that although the logit models are adequate for some purposes, they are unable to provide a good enough representation of reality when correlation between alternatives is significant, as in some aspects of modal split and route choice modelling. In these cases the multinomial probit model, based on multivariate normal cost distributions, appears to provide an acceptable alternative. Unfortunately analytic solutions are not available for problems with more than two choice alternatives, and recourse has to be made to approximate solutions, with their attendant problems of long computation time or inaccuracy. The best existing numerical approximation is provided by the 'Clark' method which, although usually of sufficient accuracy, sometimes gives rise to significant errors. A new approximation method is described in outline which, at the expense of some additional complexity, provides significantly better accuracy than the Clark method, especially for small choice probabilities. (Copyright (c) Crown Copyright 1982.)