Alcohol and drug presence in traffic crash fatalities before and after the COVID-19 pandemic: Evaluation of the fatality analysis reporting system (FARS) and linked medical examiner-vital records data in Clackamas, Multnomah, and Washington County, Oregon, 2019-2021.

Traffic fatalities, with and from increased risky behaviors (reduced seat belt use, increased impairment from licit and illicit substances), have been increasing, especially during the COVID-19 pandemic. Death certificates are a major source of epidemiologic data in the United States, but have known underreporting of drug and alcohol presence. The Fatality Analysis Reporting System (FARS) is one major source of data on fatal crashes with intoxication. This study links FARS data for three counties in Oregon (2019-2021) with local medical examiner and death certificate data (FARS source data) and compares their concordance with blood alcohol concentration and toxicology for three major drug classes by year. For drivers only, our study finds good concordance between FARS and its source data in 2019 but poor concordance in 2020. This discordance may impact future analysis of impaired crash deaths, and we list some suggestions for amelioration.