A Paired Combinatorial Logit Route Choice Model with Probit-Based Equivalent Impedance

An improved paired combinatorial Logit route choice model with Probit-based equivalent route impedance is proposed to simplify the calculation and resolve the homoscedasticity problem of the Logit model. The model comprises a two-level structure: the lower level employs a binary Probit choice model to address the problem of route overlapping. Clark's approximation for normal distribution is employed to compute the equivalent impendence for each route pair in the upper level. The homoscedasticity problem is resolved through the introduction of the normal distribution. The upper level is a classical multinomial Logit model with relative impedance that reduces the defect of variance-homogeneity in the upper level. The probability of route selection is determined by marginal and conditional probabilities. The proposed model combines the advantages of both Probit and Logit models with close-form formulations, which can be easily calculated. Two numerical tests, which were performed on the well-known examples, indicate that the proposed model produces more reasonable and stable results.