This paper investigates the impacts of COVID-19 safer-at-home polices on collisions and pollution. We find that statewide safer-at-home policies lead to a 20% reduction in vehicular collisions and that the effect is entirely driven by less severe collisions. For pollution, we find particulate matter concentration levels approximately 1.5 μg/m³ lower during the period of a safer-at-home order, representing a 25% reduction. We document a similar reduction in air pollution following the implementation of similar policies in Europe. We calculate that as of the end of June 2020, the benefits from avoided car collisions in the U.S. were approximately $16 billion while the benefits from reduced air pollution could be as high as $13 billion.

本文调查了 COVID-19 居家安全政策对碰撞和污染的影响。我们发现，全州范围内的居家安全政策可使车辆碰撞事故减少 20%，而且这种影响完全是由不太严重的碰撞事故造成的。对于污染，我们发现在执行居家安全令期间，颗粒物浓度水平降低了约 1.5  μ g/m ^{3 ，即降低了 25%。}在欧洲实施类似政策后，我们记录了类似的空气污染减少情况。我们计算得出，截至 2020 年 6 月底，美国避免汽车碰撞带来的收益约为 160 亿美元，而减少空气污染带来的收益可能高达 130 亿美元。