A study of highway logistics transportation network structure in China: From the perspective of complex network

City networks have been widely studied from various perspectives. By analyzing the highway logistics transportation data in China, this paper builds a highway logistics transportation network (HLTN) as a new kind of city network with the time span over three years based on complex network theory. Both local and global indicators are employed to characterize the HLTN in this study. Specifically, the global topologies of HLTN are explored through analyzing global network-based indicators, it is found that the HLTN exhibits a small-world network property with a decreasing average shortest path and an increasing clustering coefficient over three years. The cumulative degree distribution of HLTN follows exponential function, which means a few cities account for most of China's overall highway logistics transportation. The local topologies of HLTN are also investigated through degree centrality, betweenness centrality and closeness centrality. Furthermore, to access the cities' highway logistics transportation capacity comprehensively, we design a mixture network-based index by using principal component analysis approach. The results reveal that the overall transportation capacity of highway logistics is improving as time goes on and the proposed index can be presented as an appropriate proxy for connectivity. Finally, we apply real capacity-based indicator and the proposed mixture network-based index to reveal the hierarchical structure of cities in highway logistics transportation by using agglomerative hierarchical clustering method. The results indicate that the highway logistics transportation capability among cities is unbalanced distributed, but the differences of the unbalance is decreasing which show a trend of balanced development. The findings from the designed HLTN shed light on the panorama of highway logistics transportation from the lens of complex network and can further guide logistics infrastructure development in China.