The intricate relationship between transportation infrastructure and public health has long intrigued urban planners, economists, and public health officials alike. Recent research sheds new light on this dynamic by investigating how both intra-city and inter-city transportation developments in China affect the health of laborers, who constitute a significant portion of the urban workforce. This study utilizes rigorous econometric methods and multi-dimensional health metrics to unravel the nuanced ways in which transportation networks influence health outcomes, offering valuable insights into urban health policy and infrastructure investment strategies.
Starting with intra-city transportation infrastructure, the research examines whether improvements at the community level, such as the introduction of bus stations and enhancement of community roads, contribute to better health outcomes among laborers. Employing fixed-effects models that control for provincial, community, and household variables, findings consistently indicate no significant relationship between proximity or access to bus stations and the recent illness rates of laborers. This lack of statistical significance persists even when stratifying the urban population by household registration status, a crucial factor in China given the disparities in healthcare access between rural-registered migrants and urban-registered residents.
Methodologically, the study addresses the binary nature of the illness variable by applying both linear probability models and Probit regressions to ensure robustness. Neither modeling approach yields evidence supporting health improvements resulting from enhanced intra-city transport access. Complementing these analyses, body mass index (BMI) and self-rated health indices are employed as alternative health metrics, neither of which display meaningful changes attributable to intra-community road upgrades. These findings suggest that, within cities, the marginal benefit of improving bus stations or roads on immediate health statuses is limited.
One plausible explanation for this phenomenon is the inherently high accessibility of healthcare facilities within city boundaries. Statistical appendices reveal that residents typically live within one kilometer of a primary hospital and less than four kilometers from tertiary care centers, distances that can often be covered on foot or via minimal transportation. Consequently, the presence or absence of additional intra-city transport options might not significantly alter health-seeking behavior or outcomes. Moreover, the endogenous placement of transportation infrastructure—predominantly concentrated in more populous areas—is accounted for via instrumental variable (IV) techniques using population size to mitigate selection bias, yet the results remain statistically insignificant.
The landscape shifts markedly when the analysis turns to inter-city transportation infrastructure. Here, highway density, a proxy for the quality and extent of transport networks connecting cities, emerges as a potent determinant of laborers’ health. Regression results demonstrate that increased inter-city highway density correlates with statistically significant reductions in reported illness rates. These outcomes retain consistency after adjusting for spatial fixed effects and household characteristics, pointing to a robust effect beyond regional or personal heterogeneity.
Crucially, the benefits of enhanced inter-city connectivity appear to be unequally distributed. When disaggregating by household registration status, only urban-registered laborers experience health gains, while rural migrants within cities show no comparable improvements. This divergence likely reflects systemic barriers to healthcare access for migrants, such as institutional discrimination and lower socioeconomic status, which inhibit their ability to capitalize on better inter-city transport despite residing in urban environments.
To further substantiate these results, the study incorporates additional health indicators, notably BMI and self-rated health measures. Both reveal favorable trends linked to increases in highway density between cities, with laborers exhibiting healthier BMI profiles and higher subjective health assessments. These findings echo prior literature suggesting that transportation infrastructure improvements foster greater health capital, potentially via enhanced access to superior healthcare services, expanded economic opportunities, or improved health-related information dissemination.
Addressing potential endogeneity concerns, the researchers utilize historical railway station locations from 1961 as instrumental variables. This strategy leverages the persistence of transport corridors shaped by historic infrastructure investment, under the assumption that such historical factors influence present highway development but do not directly affect current health outcomes except through transportation channels. The IV estimation not only confirms the negative association between inter-city transportation density and illness but also improves causal inference, reinforcing the argument for a genuine effect.
In a further methodological advance, the study employs double machine learning (DML) techniques to flexibly model the complex relationships between control variables, transport infrastructure, and health. This approach combines machine learning’s predictive power with traditional causal inference frameworks to correct model specification bias. Consistent with previous results, the DML estimations affirm the statistically significant positive health impacts of improved inter-city transport infrastructure, highlighting the robustness of these findings across various analytical paradigms.
An important behavioral mechanism underlying these effects emerges from the analysis of long-distance medical treatment-seeking patterns. Data indicate that improved inter-city networks facilitate access to higher-level healthcare facilities located in prefecture-level cities, which house more advanced tertiary hospitals compared to county-level counterparts. The improved accessibility encourages patients from smaller cities to seek medical care in urban centers, effectively leveraging the concentration of medical resources and potentially raising overall health outcomes.
This structural shift in health service utilization is further evidenced by subgroup analyses. Laborers residing in county-level cities and cities with scarce medical resources derive pronounced health benefits from transportation infrastructure enhancements, suggesting that where local healthcare is insufficient, connectivity to larger, resource-rich cities is critical. Contrastingly, improvements in transport do not significantly affect the health of individuals already residing in well-served urban areas, emphasizing the role of transportation as an enabler of spatial healthcare access disparities.
The behavioral findings extend to the examination of hospital choice related to medical treatment. The study reports that inter-city transportation improvements increase the likelihood of laborers obtaining treatment in local prefecture-level cities or other cities rather than in their immediate living communities. This redistribution highlights a substitution effect where better transport diminishes the necessity of relying solely on proximal, often lower-level facilities by expanding viable options for medical care.
Collectively, these insights offer compelling evidence that investments in inter-city transportation infrastructure can yield substantial public health dividends by reducing illness prevalence and improving health status via expanded healthcare access and better health-seeking options. While intra-city transportation upgrades alone seem insufficient to drive health improvements, they remain a vital complement to broader regional transport strategies that integrate spatial healthcare disparities and institutional barriers.
Moreover, the study reinforces the critical importance of considering population heterogeneity, such as household registration status and urban-rural divides, in evaluating infrastructure impacts on health. Policymakers and planners seeking to maximize health benefits from transportation investments should thus account for social and economic dimensions that may modulate the capacity of different groups to benefit equally from improved connectivity.
In sum, this research contributes a nuanced understanding of how transportation infrastructure shapes health outcomes in complex urbanizing environments. By rigorously addressing potential confounders and employing sophisticated econometric methods, it highlights a pathway through which transportation improvements translate into tangible health gains, particularly by facilitating access to advanced healthcare services beyond immediate residential areas. These findings illuminate a critical intersection of urban infrastructure development and public health, with significant implications for sustainable and equitable urban policy design.
Looking forward, future investigations might explore complementary interventions that enhance healthcare accessibility for marginalized populations, particularly rural migrants in urban settings. Addressing these persistent disparities is essential to ensure that transportation-facilitated health improvements are inclusive and comprehensive. Additionally, longitudinal studies capturing dynamic changes in health behaviors and service utilization patterns as transportation networks evolve would further enrich understanding and guide effective infrastructure planning.
In an era characterized by rapid urbanization and increasing public health challenges, such evidence-based insights are invaluable. They underscore that the health benefits of transportation infrastructure extend beyond mere physical connectivity, encompassing profound implications for social equity, healthcare access, and ultimately, human well-being. For urban centers striving to foster healthy, resilient populations, integrating transportation planning with health policy emerges as an imperative agenda for sustainable development.
Subject of Research: The impact of intra-city and inter-city transportation infrastructure on laborers’ health status in urban China.
Article Title: Transportation infrastructure and good health in urban China.
Article References:
Bu, T., Tang, D. Transportation infrastructure and good health in urban China.
Humanit Soc Sci Commun 12, 722 (2025). https://doi.org/10.1057/s41599-025-05060-y
Image Credits: AI Generated
