Supply Chain Models for Freight Transportation Planning

This study investigates the applicability of a supply chain based modeling methodology for regional freight transportation planning. This methodology attempts to relate the supply chain practices of individual firms to public sector transportation planning. A two-step methodology that makes use of some of the supply chain characteristics is proposed for freight transportation planning. The first step of the methodology is to obtain the O-D Flows by tracing the supply chains of major business units in a region. This step is illustrated using the sales volume data of a truck manufacturer in Virginia. The second step is to model the choice of mode for freight shipments. The logistical needs and constraints of a shipper determine the choice of mode. Therefore, a model that accounts for the logistical variables would be appropriate for modeling the choice of mode. A list of supply chain variables that have the potential to influence the choice of mode is identified. A common problem that is usually reported in modeling the choice of mode is the lack of availability of reliable disaggregate data. An attempt has been made to develop a mode choice model using aggregate data from TRANSEARCH database supplemented with data from a survey of shippers. This survey also colleted data pertaining to relative weights among potential attributes that affect the choice of mode for three different categories of shippers. The mode choice model was developed using four different classification methods, namely: Binary Logit Model, Linear Discriminant Analysis, Quadratic Discriminant Analysis and Tree Classification. The advantages and disadvantages of using these methods for mode choice analyses are discussed.