Previous studies evaluating the impacts of transport interventions on accessibility to healthcare have largely overlooked competition among patients for limited resources and the tendency to use healthcare located closer to them (i.e., distance decay effects). This study aims to demonstrate how overlooking supply-demand dynamics and distance decay effects can distort the evaluation of a new public transit service's impacts on healthcare accessibility and inequalities. Specifically, using a new bus rapid transit (BRT) service in Columbus, Ohio, USA, as an example, we compare three types of measures: 1) cumulative-opportunity, 2) multimodal two-step floating catchment area (2SFCA), and 3) multimodal generalized 2SFCA (G2SFCA) accessibility metrics. To understand the similarities in results obtained from different accessibility measures, we use the Pearson correlation coefficients of standardized accessibility change scores. Further, we leverage an inequality index, the Palma ratios, to examine how inequality assessments can be sensitive to the choice of accessibility measure. The correlation analysis reveals notable differences among the three measures. This indicates that neglecting supply-demand dynamics and distance decay effects can lead to differences in results, potentially distorting transit project evaluations and misleading stakeholders. Moreover, although overall conclusions about inequalities are largely consistent, we observed nuanced and statistically significant differences in Palma ratios when derived from cumulative-opportunity metrics compared to the multimodal 2SFCA and multimodal generalized 2SFCA measures. Our findings underscore the importance of considering supply-demand dynamics and distance decay effects for a more realistic and accurate assessment of new transit service's impacts on healthcare accessibility and inequalities.

中文翻译：

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评估供需动态和距离衰减效应对公共交通项目评估的影响：医疗保健可及性和不平等的研究

先前评估交通干预措施对医疗保健可及性影响的研究在很大程度上忽视了患者之间对有限资源的竞争以及使用距离较近的医疗保健服务的倾向（即距离衰减效应）。本研究旨在证明忽视供需动态和距离衰减效应会如何扭曲对新公共交通服务对医疗保健可及性和不平等影响的评估。具体来说，以美国俄亥俄州哥伦布市的一项新的快速公交（BRT）服务为例，我们比较了三种类型的措施：1）累积机会，2）多式联运两步浮动集水区（2SFCA），以及3）多模态广义2SFCA（G2SFCA）可达性度量。为了了解不同可达性测量结果的相似性，我们使用标准化可达性变化分数的皮尔逊相关系数。此外，我们利用不平等指数（帕尔马比率）来研究不平等评估如何对可达性衡量标准的选择敏感。相关性分析揭示了这三个指标之间存在显着差异。这表明，忽视供需动态和距离衰减效应可能会导致结果差异，可能会扭曲交通项目评估并误导利益相关者。此外，尽管关于不平等的总体结论基本一致，但与多模态 2SFCA 和多模态广义 2SFCA 度量相比，我们观察到从累积机会指标得出的帕尔马比率存在细微差别和统计显着差异。我们的研究结果强调了考虑供需动态和距离衰减效应的重要性，以便更现实和准确地评估新交通服务对医疗保健可及性和不平等的影响。