ORIGINAL RESEARCH article
Front. Sustain. Cities
Sec. Urban Transportation Systems and Mobility
Volume 7 - 2025 | doi: 10.3389/frsc.2025.1681723
How does the built environment in high-density cities affect subway travel for the older adults: Insights from travel chain and explainable machine learning
Provisionally accepted
- 1Hunan City University School of Architecture and Urban Planning, Yiyang, China
- 2Tongji University College of Architecture and Urban Planning, Shanghai, China
- 3Tongji University College of Civil Engineering, Shanghai, China
- 4Shentong Metro Group Co.Ltd., Shanghai, China
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This study examines how built environment factors shape metro travel patterns among older adults in high-density urban environments, utilizing large-scale metro smart card data from Shanghai. By integrating a Geographically Weighted Random Forest model with SHAP interpretability methods, the research identifies older adults' travel chains and identifies key built environment determinants that influence their metro travel destination stations. Results reveal that functional facilities, particularly shopping, living services, and government facilities, are the driving force of metro usage among older adults, while traditional density measures like intersection density and floor area ratio exhibit limited influence due to saturation effects in highly developed urban contexts. Nonlinear analyses reveal optimal thresholds for various facilities and green spaces, highlighting older adults' preference for moderate provision over excessive density and complexity. In the interaction effect analysis, the combination of POI diversity and intersection density exhibits pronounced synergistic or suppressive effects, highlighting their complex interaction influence on metro travel behavior. Furthermore, clustering analysis categorizes metro stations into distinct types based on population density and destination ridership, revealing localized effects and spatial heterogeneity in built environment impacts. This research contributes methodologically and This is a provisional file, not the final typeset article empirically to understanding older adults' metro mobility, providing evidence to support targeted, inclusive urban transportation policies.
Keywords: older adults1, travel chain2, built environment3, nonlinear relationships4, high-density5
Received: 02 Sep 2025; Accepted: 29 Sep 2025.
Copyright: © 2025 LU, Fan, Zhang, Jiang, Liu, Chen and Chen. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Zheng Chen, zhengchen@tongji.edu.cn
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