3. Network Structure
The aggregated transportation network representation in Fig. 1 depicts the shipper network. Fig. 2
represents the detailed, multimodal carrier transportation network. The shipper network includes nodes
representing origin markets, destination markets and transshipment points. The supply and demand are
associated with the origin and destination nodes, respectively, and delivery routings are shown along
transshipment nodes located between the origin and destination nodes. Links connecting these nodes
indicate alternative delivery routes.