A new analysis led by a Colorado State University researcher has found that after Utah lowered its legal blood alcohol concentration for driving, alcohol-related crash fatalities declined significantly more in Utah compared to its six contiguous states.
The findings from the study in the American Journal of Preventive Medicine provide timely evidence that lowering the BAC limit may save lives and point to broad public safety benefits.
Utah reduced its blood alcohol concentration, or BAC, limit for driving from 0.08 to 0.05 grams per deciliter (g/dL) in a law passed in 2017.
Driving under the influence of alcohol remains a major risk factor for motor vehicle crashes, with recent data showing a stagnation of reductions or rise in fatalities over the past decade. In 2023, 12,429 crash fatalities in the U.S. involved at least one alcohol-impaired driver. Over the period 2014-2023, alcohol-impaired driving crashes have consistently accounted for 28%-32% of all annual traffic fatalities in the U.S.
Past research
International research has consistently demonstrated that lowering the legal BAC limit to 0.05 effectively reduces alcohol-related crash injuries and fatalities by 11% or more. Utah was the first U.S. state to lower the legal BAC limit for driving from 0.08 to 0.05 – the law was passed in 2017 and took effect in 2018 – and remains the only state that enforces the lower limit. To date, all other states maintain a 0.08 threshold.
Investigators of the current study analyzed national fatal crash data from the Fatality Analysis Reporting System and compared county-level crash fatality in Utah with that in Arizona, Colorado, Idaho, Nevada, New Mexico and Wyoming before and after the Utah 0.05 BAC law took effect (2013-2023).
The most important finding was that Utah experienced larger declines in alcohol-related fatalities, while non-alcohol-related fatalities did not show the same policy-related change.
“This is one of the most rigorous US-based evaluations of a 0.05 BAC law using county-level comparative data,” said lead author and co-investigator Kaigang Li, an associate professor in CSU’s Department of Health and Exercise Science and the Colorado School of Public Health. “At a time when alcohol-impaired driving deaths remain a persistent national public health problem, these findings provide timely evidence that lowering the BAC limit may save lives.”
Broad deterrent
The researchers were highly encouraged to see that reductions were not only limited to drivers near the 0.05 threshold but extended across higher BAC levels as well. This suggests the law may have had a broader deterrent effect on drinking and driving behavior.
Despite documented lifesaving policy benefits in Utah and other nations and strong endorsement from the National Transportation Safety Board, political resistance, public misunderstanding and cultural norms remain barriers to adopting a national 0.05 BAC limit, the investigators point out.
“In the last decade for which we have federally published U.S. crash data available, the number of alcohol-impaired driving crash fatalities increased by 25%, and the corresponding fatality rate increased by 15%,” said lead investigator Federico E. Vaca of the University of California Irvine School of Medicine, Irvine. “There is just so much opportunity here for collective prevention efforts to reduce serious injury and save more lives on our roadways. Each year of delay in enacting this policy represents a lost opportunity to prevent thousands of fatalities among drivers, passengers and all road users.”
Li concluded, “Our findings suggest that stronger impaired-driving laws can influence drivers’ behavior and reduce preventable traffic deaths. Utah’s experience shows important and additional evidence for policymakers nationwide.”
The article is openly available for 30 days as of June 16 at https://www.ajpmonline.org/article/S0749-3797(26)00123-6/fulltext . The work was supported by the National Institute on Alcohol Abuse and Alcoholism of the National Institutes of Health. The American Journal of Preventive Medicine is published by Elsevier.
American Journal of Preventive Medicine
Data/statistical analysis
People
Utah’s Move From 0.08 to 0.05 Blood Alcohol Concentration Per Se Policy: Effects on Driver Crash Fatalities Compared With Contiguous States
13-May-2026