Evaluation on support of China’s comprehensive transportation corridors for urban agglomeration development

Comprehensive transportation corridors serve as strategic channels for regional resource flows and form the backbone of urban agglomeration spatial organization, playing a crucial role in their high-quality development. However, existing research lacks focus on their interaction mechanisms and support force measurement. Grounded in transportation geography theory, this study systematically examines the feedback mechanisms between transportation corridors and urban agglomeration development. It introduces an innovative four-dimensional assessment system—“quantity-quality-resilience-green”—and conducts an empirical analysis of major urban agglomerations in China. Key findings include: 1) Comprehensive transportation corridors constitute a four-phase coupled regional system—“point-network-flow-region”-emerging as an inevitable outcome of urban system evolution toward regional integration. Their formation and urban agglomeration development follow a pattern of “connecting points into networks, shaping flows through networks, promoting regions through flows, and generating points through regions”. 2) Evaluating corridor support across the four dimensions reveals that transportation supply largely aligns with regional demand, with the Yangtze River Delta corridor playing a particularly strong role. Based on the score composition, the support role of the corridor is mainly constrained by two-factor and three-factor models, with facility scale and transportation efficiency having a significant impact on support force. 3) While corridor support and economic development exhibit high coupling coordination, alignment with urbanization rates remains relatively weak, highlighting a significant spatial-temporal mismatch between corridor supply and population concentration. From an “axis-cluster” perspective, this study proposes strategies such as dynamic supply-demand matching, optimizing transportation network coordination, and aligning with national strategic needs. The construction and improvement of comprehensive transportation corridors are not only key components of building a strong transportation nation but also a fundamental supply-side support for the development of China’s “19+2 urban agglomerations”. The connection and coordination between the two should not be overlooked. By enriching transportation geography theory, it provides critical scientific support for urban agglomeration development and the advancement of a transportation-driven national strategy.