Unpacking the COVID-19 roadway fatality paradox: an analysis of motor vehicle crashes in Michigan 2019-2022.

Abstract

Objectives: Motor vehicle travel shifts during the COVID-19 pandemic resulted in fewer vehicle miles traveled yet paradoxically higher fatality rates. Anecdotally, the paradox was blamed on increases in risky behavior in the absence of regular traffic and enforcement. We examined three hypotheses to explain the fatality paradox using Michigan crash data: (1) lack of congestion led to higher-speed impacts; (2) increased risky driver/driving; and (3) low-risk driving miles decreased.

Methods: We examined changes in hypotheses-related crash factors and injury outcomes for the years 2019-2022; restricted to the duration of Michigan's stay-at-home order in 2020 (March 23 and June 1). First, we used logistic regression to evaluate the prevalence of the crash factors in all crashes and in severe/fatal crashes only in 2020, 2021; and 2022 compared to 2019. Second, to identify whether those crash factors differentially resulted in worse injury outcomes, we used logistic regression to evaluate whether odds of a severe/fatal crash occurring in March 23-June 1 across the years 2019-2022.

Results: All three hypotheses tested to explain Michigan's traffic safety paradox had moderate to extensive support. Risky driving/driver factors were more prevalent during the 2020 stay-at-home order in all crashes; however, the risky driving factors were largely not more prevalent in severe and fatal injury crashes in 2020. In contrast, although less prevalent, many factors associated with the low-risk mileage and congestion hypotheses were more likely to result in severe and fatal outcomes during the stay-at-home orders in 2020. The prevalence of most congestion and low-risk miles factors remained less prevalent in 2020-2022 compared to 2019; while the prevalence of risky driving and driver factors in crashes had largely returned to 2019 levels or lower in 2022.

Conclusions: The overlapping contributions of the three different hypotheses explaining Michigan's pandemic traffic safety paradox underscore the complexity of roadway safety and the need for simultaneous investments in driving education, environmental infrastructure, and technology-based mechanisms of enforcement. In the post-pandemic new normal, system-wide changes from investments like these can encourage safer driving even in the absence of social pressure or physical law enforcement presence.