Assessing the impact of urban place irreplaceability on intercity travel mode choice

Understanding the relationship between intercity travel modes and the built environment from a functional perspective is essential for supporting and improving transportation services, coordinating regional development, and promoting regional sustainability. In urban regions, residents often engage in intercity travel to seek specific functions and services, and the choice of travel mode is closely related to the purpose of the trip. However, there has been limited research on the impact of differences in urban functions on intercity travel modes. In this study, we use irreplaceability (a measure of function uniqueness and scarcity of a place) to analyze the variations in the functions of different urban places and further examine the relationships between the functional aspects of the built environment and intercity travel modes. We conduct an empirical analysis of this relationship within the Shanghai–Suzhou urban region (China). The results indicate that, along with traditional morphological measures of the built environment, the irreplaceability of destinations displays a significant and important relationship with intercity travel modes. The selection of certain travel modes is driven by the desire to access unique services in destination cities. The strong functional irreplaceability of urban places is associated with frequent use of regional rail transit, whereas places with low irreplaceability are associated with road transit. Furthermore, the accessibility of regional rail transit stations moderates the effect of functional irreplaceability. The accessibility of regional rail transit stations enhances the role of irreplaceability, whereas the accessibility of expressways significantly suppresses it. This suggests that, within the Shanghai–Suzhou area, the most irreplaceable functions are best supported by regional rail transit. This study enhances the built environment framework by incorporating function measurements of irreplaceability, offering valuable insights into the sustainable development of intercity travel.