Summary:
The COVID-19 pandemic resulted in substantial disruptions to travel behavior and transportation systems across the United States. While traffic volumes declined sharply during the early stages of the pandemic, many jurisdictions experienced increases in traffic fatalities and serious injuries. Understanding the factors contributing to these changes is critical for improving roadway safety and informing future policy responses. This study investigates trends in traffic fatalities following the COVID-19 pandemic using a multi-scale analytical framework. The analysis first examines fatality trends at the national level using state-level and county-level data for the period 2019– 2023. These analyses provide a broad understanding of how traffic safety outcomes evolved across the United States during and after the pandemic. The study then focuses on Michigan, where more detailed crash data enabled a deeper investigation of contributing factors. Michigan analyses were conducted at multiple spatial and analytical levels, including county-level fatality trend analyses, roadway segment-level crash analyses, and party-involved severity analyses using crash records from the Michigan State Police Traffic Crash Reporting System for the period 2019–2024. The segment-level analyses were conducted separately across five roadway facility types, including freeways, multilane divided highways, multilane undivided highways, rural two-lane roads, and urban two-lane highways. These data were supplemented with roadway inventory information and probe vehicle speed data to examine how roadway characteristics, operating speeds, traffic conditions, and driver-related factors influence crash outcomes and injury severity. The results highlight significant changes in roadway safety trends following the onset of the pandemic. Although reductions in traffic demand initially reduced overall crash frequencies, increases in risky driving behaviors and changes in travel patterns contributed to higher fatality rates in many locations. In particular, the analyses suggest that changes in driver behavior, including increased speeding, higher rates of impaired driving, and reductions in seat belt use, played an important role in the observed increases in fatal and severe injury crashes following the pandemic. Detailed analyses of Michigan crash data provide further insight into the roadway, environmental, and behavioral factors associated with severe crash outcomes across different roadway facility types. Based on these findings, the study identifies several countermeasures that may help mitigate increases in fatalities and serious injuries. These strategies include infrastructure improvements, targeted enforcement efforts, and safety interventions aimed at reducing high-risk driving behaviors and improving protection for vulnerable road users. The findings provide important insights for transportation agencies seeking to improve roadway safety and develop resilient strategies for responding to future disruptions in travel behavior.
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