Problem statement
As previously stated, it is assumed that an order can be delivered by two kind of road transport modes, LTL shipment or FTL. The transportation mode is, therefore, the main decision variable. Although motor carrier cost functions may be developed according to different criteria (Christensen and Huston, 1987; Harmatuck, 1992), the typical cost for a LTL shipment of weight W to a geographical zone Zj is: