This article examines the effects of two widely used geomasking methods (aggregation and the bimodal Gaussian method) on errors in car- and transit-based travel times from people's homes to health facilities using Cook County in Illinois as a case study area. It addresses two research questions: (Q1) How do the effects of geomasking on travel time errors differ between transportation modes? (Q2) How do errors in car- and transit-based travel times differ between urban and suburban areas? The results indicate that geomasking introduces considerable errors in travel times. Specifically, errors in transit-based travel times are significantly higher than those in car-based travel times. Moreover, when large radii are used for geomasking, errors in car-based travel times in urban areas are significantly higher than those in suburban areas. On the contrary, transit-based travel time errors in urban areas are significantly lower than those in suburban areas. Because transportation modes and urban area types play essential roles in travel time errors caused by geomasking, researchers need to mitigate these errors when using geomasked locations for their analysis (e.g., evaluating the spatial accessibility of certain facilities, such as hospitals or healthy food outlets).

中文翻译：

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地理掩蔽导致的旅行时间误差可能因交通方式和城市区域类型而异

本文以伊利诺伊州库克县为例，研究了两种广泛使用的地理掩蔽方法（聚合和双峰高斯方法）对从人们家到医疗机构的基于汽车和公交的旅行时间误差的影响。它解决了两个研究问题：（Q1）地理掩蔽对旅行时间误差的影响在不同交通方式之间有何不同？（Q2）城市和郊区之间基于汽车和公共交通的旅行时间误差有何不同？结果表明地理掩蔽在旅行时间中引入了相当大的误差。具体而言，基于公交的旅行时间的错误明显高于基于汽车的旅行时间的错误。此外，当使用大半径进行地理掩蔽时，城市地区基于汽车的旅行时间的误差明显高于郊区。相反，城市地区基于公交的出行时间误差明显低于郊区。由于交通方式和城市地区类型在由地理掩蔽引起的旅行时间误差中起着至关重要的作用，研究人员在使用地理掩蔽位置进行分析时需要减少这些误差（例如，评估某些设施的空间可达性，如医院或健康食品店） .