To accommodate the similarity between alternatives,the Nested Logit( NL) model is usually applied to construct sub-models in RP / SP combined analysis. In previous literatures,however,RP and SP sub- models often adopt different hierarchical structures,which result in problems such as inconsistent comprehension for behavioral mechanisms,unclear corresponding relation between error- components and incorrectly description of the real hierarchical structure of SP data. This paper formulates a joint method,which...