IN THIS STUDY, A JOINT COST FUNCTION IS SPECIFIED AND ESTIMATED FROM A SAMPLE OF LARGE CLASS 1 US MOTOR CARRIERS OF GENERAL COMMODITIES. IN THIS COST FUNCTION SPECIFICATION, LESS-THAN-TRUCKLOAD (LTL) TRAFFIC AND TRUCKLOAD (TL) TRAFFIC ARE TREATED AS SEPARATE OUTPUTS EACH OF WHICH IS DESCRIBED BY THE CARRIER'S ANNUAL NUMBER OF SHIPMENTS, AVERAGE SHIPMENT SIZE AND LENGTH OF HAUL. INPUTS ARE AGGREGATED INTO LINE HAUL, PICKUP AND DELIVERY, HANDLING, AND BILLING AND COLLECTING ACTIVITIES. ACTIVITY PRICES ARE USED IN THE COST FUNCTION SPECIFICATION. RESULTS SUGGEST THAT (1) MARGINAL COST FUNCTION FOR TL AND LTL TRAFFIC ARE DIFFERENT AND REQUIRE A MULTIPLE OUTPUT SPECIFICATION, (2) TL TRAFFIC HAS AN IMPORTANT EFFECT ON THE PROVISION OF LTL SERVICES, AND (3) A FLEXIBLE FUNCTIONAL FORM OF THE COST FUNCTION IS NECESSARY FOR THE COMPLEX NATURE OF MOTOR CARRIER COSTS.
Samenvatting