This paper examines changes in people's mobility over a 7-month period (from March 1st to September 30th, 2020) during the COVID-19 pandemic in the U.S. using longitudinal models and county-level mobility data obtained from people's anonymized mobile phone signals. It differentiates two distinct waves of the study period: Wave 1 (March–June) and Wave 2 (June–September). It also analyzes the relationships of these mobility changes with various social, spatial, policy, and political factors. The results indicate that mobility changes in Wave 1 have a V-shaped trend: people's mobility first declined at the early stage of the COVID-19 pandemic (March–April) but quickly recovered to the pre-pandemic mobility levels from April to June. The rates of mobility changes during this period are significantly associated with most of our key variables, including political partisanship, poverty level, and the strictness of mobility restriction policies. For Wave 2, there was very little mobility decline despite the existence of mobility restriction policies and the COVID-19 pandemic becoming more severe. Our findings suggest that restricting people's mobility to control the pandemic may be effective only for a short period, especially in liberal democratic societies. Further, since poor people (who are mostly essential workers) kept traveling during the pandemic, health authorities should pay special attention to these people by implementing policies to mitigate their high COVID-19 exposure risk.

本文使用纵向模型和从人们的匿名手机信号中获得的县级流动性数据，研究了美国 COVID-19 大流行期间 7 个月内（​​2020 年 3 月 1 日至 9 月 30 日）人们流动性的变化。它区分了研究期间的两个不同的波次：第 1 波（3 月至 6 月）和第 2 波（6 月至 9 月）。它还分析了这些流动性变化与各种社会、空间、政策和政治因素的关系。结果表明，第一波流动性变化呈现V形趋势：人们的流动性在COVID-19大流行初期（3月至4月）首先下降，但在4月至6月迅速恢复到大流行前的流动性水平。这一时期的流动性变化率与我们的大多数关键变量显着相关，包括政治党派、贫困水平和流动限制政策的严格程度。对于第二波，尽管存在流动性限制政策且 COVID-19 大流行变得更加严重，但流动性下降幅度很小。我们的研究结果表明，限制人们的流动以控制疫情可能只能在短期内有效，尤其是在自由民主社会。此外，由于穷人（主要是基本工作人员）在大流行期间不断旅行，卫生当局应特别关注这些人，实施政策以减轻他们的高 COVID-19 暴露风险。