Gravity law in the Chinese highway freight transportation networks

The gravity law has been documented in many socioeconomic networks, which states that the flow between two nodes positively correlates with the strengths of the nodes and negatively correlates with the distance between the two nodes. However, such research on highway freight transportation networks (HFTNs) is rare. We construct the directed and undirected highway freight transportation networks between 338 Chinese cities using about 15.06 million truck transportation records in five months and test the traditional and modified gravity laws using GDP, population, and per capita GDP as the node strength. It is found that the gravity law holds over about two orders of magnitude for the whole sample, as well as the daily samples, except for the days around the Spring Festival during which the daily sample sizes are significantly small. Accordingly, the daily exponents of the gravity law are stable except during the Spring Festival period. The results also show that the gravity law has higher explanatory power for the undirected HFTNs than for the directed HFTNs. However, the traditional and modified gravity laws have comparable explanatory power.

Modeling Carrier Interactions in an International Freight Transport System

This paper presents a novel multi-level hierarchical approach which models carrier interactions in international maritime freight transportation networks. Ocean carriers, land carriers and port terminal operators are considered. Port terminal operators, providing transportation services within a port complex, are regarded as a special type of the carrier, based on their behavior. The carriers make pricing and routing decisions at different parts of the multimodal network, having hierarchical relationships. Ocean carriers are regarded as the leaders in a maritime shipping market. Port terminal operators are the followers of ocean carriers as well as the leaders of land carriers. The individual carrier problem is formulated at each level using Nash equilibrium to find the optimal service charge and routing pattern for which each carrier obtains the greatest profit. Interactions among different types of carriers are captured in a three-level model. The concept of multi-leader-follower game is applied to a multi-level game. A numerical example is used to demonstrate the validity of the developed three-level model.

Modeling Carrier Interactions in an International Freight Transport System

This paper presents a novel multi-level hierarchical approach which models carrier interactions in international maritime freight transportation networks. Ocean carriers, land carriers and port terminal operators are considered. Port terminal operators, providing transportation services within a port complex, are regarded as a special type of the carrier, based on their behavior. The carriers make pricing and routing decisions at different parts of the multimodal network, having hierarchical relationships. Ocean carriers are regarded as the leaders in a maritime shipping market. Port terminal operators are the followers of ocean carriers as well as the leaders of land carriers. The individual carrier problem is formulated at each level using Nash equilibrium to find the optimal service charge and routing pattern for which each carrier obtains the greatest profit. Interactions among different types of carriers are captured in a three-level model. The concept of multi-leader-follower game is applied to a multi-level game. A numerical example is used to demonstrate the validity of the developed three-level model.