Speeding and Traffic-Related Injuries and Fatalities during the 2020 COVID-19 Pandemic: The Cases of Seattle and New York City

Liao, Felix Haifeng; Lowry, Michael · 2021 · OpenAlex-citations

DOI: 10.1101/2021.08.08.21261745

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Summary

This study investigates the paradoxical trend of stable or increasing traffic-related fatalities despite reduced vehicle volumes during the 2020 COVID-19 pandemic. While stay-at-home orders significantly lowered traffic counts and total motor vehicle collisions (MVCs) in Seattle and New York City, death tolls remained largely unchanged. The research aims to determine if the risk of severe injury or fatality per crash increased during the pandemic, specifically examining whether speeding behavior contributed to this outcome compared to other crash types, such as single-vehicle collisions or those involving pedestrians and cyclists. The authors utilized publicly available, deidentified police collision data from Seattle and New York City for the period between January 2019 and December 2020, encompassing 321,816 crashes in NYC and 16,446 in Seattle. To isolate the pandemic’s impact, the study employed a difference-in-differences (DID) econometric approach using Poisson regression. This method compared weekly crash trends in 2020 against 2019 baselines, controlling for reductions in traffic volume (proxied by highway loop detectors in Seattle and bridge/tunnel counts in NYC) and seasonal weather conditions. The analysis divided the pandemic into two phases: March–May (strict lockdowns) and June–December (partial reopening). Results indicated that while total crashes and injuries declined significantly due to lower traffic exposure, the incidence rates of speeding-related crashes causing fatal or severe injuries surged. During the March–May period, these specific crash rates increased by 7.7 times in Seattle and 4.5 times in New York City compared to expected levels. In the second phase (June–December), speeding-related severe injury and fatality rates remained significantly elevated, with incidence rate ratios of 4.158 in Seattle and 2.187 in NYC. Additionally, fatal crash rates in NYC increased by 1.468 times in the second phase. Conversely, no significant changes were observed in fatal or severe injury rates for single-vehicle collisions or those involving pedestrians and cyclists. The findings suggest that reduced traffic density created an environment conducive to speeding, leading to more severe outcomes per collision. The authors conclude that policymakers must implement targeted countermeasures, such as temporary traffic calming devices, increased speed enforcement, and public awareness campaigns, during periods of depressed travel demand. These interventions are critical to mitigating the rise in severe injuries and fatalities associated with speeding, even when overall traffic volumes are low.

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Topics

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• fatality injury trends
• incidence prevalence
• demographic disparities

Information type

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• Empirical Findings: crash risk outcomes