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Utah’s 0.05 BAC Law Is Working, New Research Shows
In A Nutshell
- Utah is the only U.S. state that lowered its legal blood alcohol limit from 0.08 to 0.05, a change that took effect at the end of 2018.
- A new study found alcohol-related driver deaths fell significantly more in Utah than in its six bordering states after the law took effect.
- The biggest drop appeared across the broadest category of drinking drivers, suggesting the law may have shifted behavior well beyond people near the new limit.
- Researchers say the law itself, rather than a general safety trend, likely drove the difference, though the study can’t rule out every other factor.
Alcohol affects drivers differently, but Utah’s legal blood alcohol limit is 0.05. Hitting that number behind the wheel in Utah means breaking the law. Cross the border into Nevada, Arizona, or 47 other states, and the same driver is still under the legal limit. That gap became real at the end of 2018, when Utah lowered its blood alcohol threshold from 0.08 to 0.05, becoming the only state in the country to do so. Critics warned the change would criminalize responsible social drinkers without making roads any safer. New research suggests the opposite happened.
A study published in the American Journal of Preventive Medicine compared driver crash fatality data in Utah against its six bordering states before and after the law took effect. Researchers found that Utah’s alcohol-related driver deaths dropped significantly more than in neighboring Arizona, Colorado, Idaho, Nevada, New Mexico, and Wyoming, where the legal limit stayed at 0.08.
This lands directly in an ongoing national argument about whether 0.08 is too lenient, one stalled for years by political resistance, public skepticism, and concerns about penalizing moderate drinkers. Utah’s results, drawn from a rigorous county-level analysis rather than a simple before-and-after snapshot, add a data point that is hard to wave away.
Utah’s Lower BAC Limit Got a County-Level Stress Test
Researchers pulled crash data from the Fatality Analysis Reporting System, a national database maintained by the National Highway Traffic Safety Administration that tracks every fatal crash on public roads. Instead of relying only on statewide totals, the team analyzed county-level data from Utah and its six neighbors, a finer-grained approach than an earlier federal review that only looked at three of those states using statewide numbers.
Two specific years anchored the comparison: 2016, the last full year before Utah’s law passed, and 2019, the first full year after it took effect. Drivers involved in fatal crashes were grouped by blood alcohol level into five categories, ranging from no measurable alcohol to a concentration of 0.15 or higher, nearly twice the old legal limit.
In total, the analysis included 7,930 drivers involved in fatal crashes across the seven states during those two years, with about 9% in Utah and the rest spread across its neighbors. Most were 25 or older, and men made up most drivers in every alcohol category and nearly three-quarters overall. Utah drivers were less likely to have any alcohol in their system, with nearly 75% showing no measurable alcohol, compared with about 62% elsewhere.
Alcohol-Related Driver Deaths Fell at Every Alcohol-Positive BAC Level
Researchers used a method that compares how much an outcome changes in one place relative to a similar place over the same stretch of time, a way of separating the change tied to Utah’s law from broader trends affecting the region. By that measure, Utah’s alcohol-related crash fatalities fell significantly more than in its neighbors, with the gap holding at every alcohol-positive threshold tested.
Biggest gap of all showed up in the broadest category: drivers with a BAC of 0.01 or higher, up through the highest levels measured. That group folds in everyone from a light drinker to someone heavily intoxicated, so the result should not be read as a story about people who’d barely been drinking. Researchers suggest it points to something broader instead, a shift in behavior reaching drivers well beyond those near the new 0.05 limit.
Crashes involving sober drivers told a different story. Both Utah and its neighbors saw fatalities decline in that category, and the difference between them was not significant, supporting the idea that the difference was tied to drinking and driving rather than a general decline across all fatal crashes.
A few explanations for why the decline may have occurred stand out, though none were directly measured in the study. A lower limit may have made more drivers feel like drinking at all carried real legal risk, prompting some to plan for a sober ride home rather than guessing whether the alcohol would wear off in time. Utah also ran visible awareness campaigns around the new threshold, and bars may have adjusted how they served alcohol once stricter enforcement became a possibility, effects the researchers suggest likely reinforced each other rather than acting alone.
Utah’s results echo what happened abroad. Australia, Austria, France, the Netherlands, and Japan have reported lasting drops in alcohol-related traffic deaths after adopting limits at or below 0.05. The World Health Organization and the National Transportation Safety Board have urged wider adoption, though political resistance and public skepticism have kept most states from following Utah’s lead.
Researchers noted the main analysis compared only two years, 2016 and 2019, limiting what it can say about longer-term effects, and other factors, like improvements in vehicle safety technology, could also be shaping nationwide trends. A longer sensitivity check comparing 2013 through 2016 with 2019 and 2021 through 2023 pointed in the same direction but did not reach statistical significance. Even so, the pattern lines up with what the law was designed to do.
Utah’s experiment with a stricter limit has produced meaningful evidence linking the policy to fewer alcohol-related driver deaths. Whether other states follow may depend less on the data and more on whether lawmakers can persuade voters that even moderate drinking can put some drivers over a 0.05 limit.
Disclaimer: This article summarizes findings from a single peer-reviewed study and is intended for general informational purposes. It is not medical, legal, or driving safety advice. Individual reactions to alcohol vary, and readers should consult official state guidelines for current legal blood alcohol limits.
Paper Notes
Limitations
The study authors acknowledged several constraints on their findings. The analysis compared only two specific years, 2016 and 2019, which limits the ability to assess whether the law’s effects held up over a longer stretch of time. County- and state-level data also cannot account for individual differences among drivers, such as age, sex, or prior offenses, that might influence crash risk. Because Utah’s law applied uniformly across the entire state, researchers could not compare areas with stronger or weaker enforcement to isolate how much enforcement intensity mattered. A supplemental analysis using a longer time window, from 2013 through 2016 compared with 2019 and 2021 through 2023, showed a similar pattern of reduced fatalities in Utah, though those results did not reach statistical significance.
Funding and Disclosures
The research was funded by the National Institute on Alcohol Abuse and Alcoholism, part of the National Institutes of Health, under award numbers R56AA031271 and R01AA032274. The authors reported no conflicts of interest. The paper includes a standard disclaimer noting that its content reflects the views of the authors and not necessarily those of the NIH.
Publication Details
The study, titled “Utah’s Move From 0.08 to 0.05 Blood Alcohol Concentration Per Se Policy: Effects on Driver Crash Fatalities Compared With Contiguous States,” was authored by Kaigang Li, James C. Fell, Niyousha Hosseinichimeh, Siwei Hu, and Federico E. Vaca. It was published in the American Journal of Preventive Medicine in 2026. The DOI is 10.1016/j.amepre.2026.108380.
