Revealed preference analysis of commercial vehicle choice process

The paper discusses modeling the commercial vehicle choice process as part of a discrete-continuous choice formulation, with the shipment size as the continuous variable, and the type of vehicle as the discrete choice, in the context of a case study. The results indicate that shipment size could be adequately modeled as a function of the trip distance, the type of commodity being transported, and the type of economic activity taking place at the origin and destination of the trip. The choice of the type of vehicle was modeled using a discrete choice formulation with variable choice sets conditioned by the shipment size. Market elasticities were estimated under two different models-a multinomial logit model and the heteroscedastic extreme value (HEV) model. It was found that the HEV model provided a more realistic assessment of the cross-elasticities of choice. The strong role played by the economic activity at the trip origin and destination suggests the need for further exploring the integration of these variables as part of commodity based modeling. Among other things, this has the potential for providing an enhanced representation of the economic linkages that determine freight demand.