Impact Effects of Transport Structure Changes on Urban Traffic Congestion: A Case Study of Core Cities in China

Accelerated urbanization and population expansion in developing countries have led to excessive reliance on road transport within logistics systems, exacerbating urban traffic congestion and constraining high-quality socioeconomic development. Consequently, optimizing urban logistics-transport structures becomes crucial for alleviating congestion and achieving sustainable economic growth. This study employs Chinese core cities as samples, adopting a comparative perspective on passenger/freight transport structure changes. Kernel density estimation and Markov chain models analyze spatiotemporal evolution patterns between logistics-transport restructuring and congestion, exploring their mechanistic relationships. Benchmark panel regressions and spatial econometric models provide empirical verification. Key findings include: (1) China’s urban logistics-transport structures demonstrate overall temporal optimization, specifically upward adjustments in passenger transport structures (rising ratios of railway-to-highway passenger volumes) and upward adjustments in freight transport structures (rising ratios of railway-to-highway freight volumes). Traffic congestion shows marginal mitigation. Changes in logistics-transport structures and spatial transitions of congestion remain relatively stable. China’s urban transportation exhibits a stepped imbalance pattern: “eastern superiority and central-western weakness in rising transport structures” alongside “eastern-central superiority and western inferiority in congestion alleviation”. (2) Nationally, absent spatial considerations, increased railway-to-highway passenger and freight volume ratios suppress congestion. When incorporating spatial factors, these ratio improvements alleviate local congestion while mitigating neighboring areas’ congestion. (3) Regionally without spatial effects, enhanced railway-passenger structures reduce congestion in eastern-western cities. Central cities’ inadequate transport network upgrades prevent full utilization of railway advantages, intensifying congestion. Improved railway-freight structures alleviate congestion in eastern-central cities, whereas western mountainous terrain constraints limit rail freight capacity, failing to meet growing demand and worsening congestion. With spatial effects, railway-freight improvements effectively reduce eastern-central congestion, while railway-passenger enhancements may exacerbate central cities’ congestion.