Passenger and freight travel patterns: A cluster analysis based on urban networks

<b>Background:</b> While research on population travel patterns and urban networks has been active, it has primarily focused on passenger travel, leaving freight travel relatively underexplored.<b>Objective:</b> This study addresses this gap by analyzing both passenger and freight travel patterns, network structures, and central areas.<b>Methods:</b> It uses origin-destination (OD) data, considering total travel volume by purpose and mode. The study applies regular equivalence and power centrality to examine differences in human and logistics flows across South Korea from an urban network theory perspective.<b>Key Findings:</b>1. <b>Passenger vs. Freight Travel Density:</b> Passenger travel, which is primarily short-distance, exhibits lower density and intensity compared to freight travel. In contrast, freight travel demonstrates significant density across short, medium, and long distances, with routes concentrated around nodal regions.2. <b>Cluster Formation:</b> Passenger travel forms several polynucleated clusters, particularly for short-distance movements. In contrast, freight travel is characterized by a few extensive clusters that span medium to long distances.3. <b>Spatial Interaction:</b> The spatial interaction in passenger travel is influenced by OD distance, unlike freight travel. Notably, the distance between central areas in freight travel is often longer than that in passenger travel. This may stem from the strategic positioning of certain suburban areas as central areas to optimize logistics efficiency.<b>Conclusion:</b> This study emphasizes the importance of morphological and functional linkages between cities by identifying inter-regional differences in passenger and freight flows. It also proposes spatial planning strategies based on urban hierarchy.