A Derived Demand Function for Freight Transportation

Abstract

An attempt has been made to improve upon existing specifications and estimations of freight demand by treating transportation as an input in the production process and estimating the derived input demand equations for rail and trucking associated with a general translog cost function. This estimation method also recognizes that rates and shipment characteristics are jointly dependent and takes this inter dependence into account in estimating the demand functions. Two tentative conclusions emerge from the findings of this paper. First, at least with respect to less-than-truckload (LTL), rail and truck transportation are largely independent. Therefore, relatively little modal misallocation of resources between rail and LTL trucking should result from ICC policies that attempt to maintain the value of service pricing structure. Second, the estimated own price elasticities of demand for rail services were sufficiently high to indicate that the railroads might not benefit from blanket rate increases but could benefit instead from selective rate cutting. It is noted that the unique methodology employed and the empirical findings described in this paper need to be verified using different data and different time periods.