Difference-in-Differences Study Finds Utah 0.05 BAC Law Produced Larger Alcohol-Related Fatality Declines Than in Six Neighboring States
A quasi-experimental study using FARS county data shows Utah’s 0.05 BAC law produced larger reductions in alcohol-related fatalities than in contiguous states. Effects appeared across BAC levels above the new threshold, pointing to a broad deterrent impact. The work supplies timely U.S. evidence for a policy already standard internationally yet stalled domestically by political and cultural factors.
The study used Fatality Analysis Reporting System data to compare pre- and post-policy periods, employing a 2016–2019 subsample for the primary contrast. Alcohol-related fatalities fell more sharply in Utah while non-alcohol fatalities showed no differential policy effect, indicating the change targeted impaired driving rather than broader safety trends. Reductions extended beyond the narrow 0.05–0.08 band into higher BAC ranges, consistent with a general deterrent shift in driver behavior.
International evidence from countries that adopted 0.05 limits shows 11% or greater reductions in alcohol-related deaths; Utah’s experience supplies the first rigorous U.S. within-country comparison. The analysis also notes that national alcohol-impaired fatalities rose 25% from 2014 to 2023, underscoring the opportunity cost of maintaining the 0.08 threshold in 49 states despite NTSB endorsement.
Political resistance and public misunderstanding remain the primary barriers to wider adoption. The findings imply that enforcement visibility and media coverage, not merely the statutory change, drive the observed effect, suggesting implementation details will determine outcomes if other states follow.
Next steps include replication with 2024–2026 data once available and evaluation of enforcement intensity and conviction rates in any new adopting jurisdictions.
NHTSA: No additional state will enact a 0.05 BAC statute before 2028 unless at least one new peer-reviewed difference-in-differences study replicates Utah’s relative reduction of 10% or more.
Sources (2)
- [1]Primary Source(https://www.ajpmonline.org/article/S0749-3797(24)00123-4/fulltext)
- [2]Supporting Source(https://www.ntsb.gov/safety/safety-studies/Documents/SR1801.pdf)