Evaluation of Utah’s .05 BAC Per Se Law [Traffic Tech]

NHTSA · 2022 · ROSA P / United States. Department of Transportation. National Highway Traffic Safety Administration

archive: archived pipeline: cataloged verified

Get this paper ↗ (full text — opens at the source; we link to it, we don't host it)

Summary

This report evaluates the impact of Utah’s 2017 legislation lowering the per se blood alcohol concentration (BAC) limit for drivers aged 21 and older from 0.08 to 0.05 grams per deciliter (g/dL). Motivated by persistent alcohol-impaired driving fatalities and recommendations from the National Transportation Safety Board, Utah became the first U.S. state to adopt this lower limit, effective December 30, 2018. The National Highway Traffic Safety Administration (NHTSA) conducted this study to assess changes in crash rates, fatalities, impaired driving arrests, driver attitudes, and economic indicators such as alcohol sales and tourism. The methodology involved coordinating with Utah state agencies to gather data on crashes, arrests, and driver perceptions, alongside analyzing NHTSA’s Fatality Analysis Reporting System (FARS) data. Statistical analyses compared measures from the 21 months following the law’s passage and the first 12 months after its implementation against baseline projections. The study also reviewed publicly available data on alcohol sales, tax revenues, and tourism to address concerns regarding potential negative economic impacts. Results indicated significant improvements in traffic safety. Time series analyses revealed reductions in almost all crash and driver-level measures during the post-implementation period. Specifically, total crashes per vehicle miles traveled (VMT) decreased by 9.6%, and injury crashes per VMT dropped by 10.8%. Alcohol involvement metrics also declined, with drivers having a BAC ≥ 0.05 decreasing by 22.5% and those with BAC ≥ 0.15 decreasing by 22.5%. FARS data showed that Utah’s fatal crash rate fell by 19.8% and fatality rate by 18.3% from 2016 to 2019, outperforming the 5.6% and 5.9% reductions seen in the rest of the United States. Contrary to fears of economic harm, alcohol sales, tax revenues, and tourism continued their pre-existing upward trends. DUI arrests did not spike drastically, though there was a slight, expected increase in arrests for drivers with BACs between 0.05 and 0.079. Public awareness surveys indicated that 22.1% of drinkers changed their behavior, primarily by arranging transportation when drinking. The study concludes that lowering the per se BAC limit to 0.05 had demonstrably positive impacts on highway safety in Utah, with reductions in crashes and alcohol involvement consistent with or exceeding prior research predictions. The findings refute concerns that the law would negatively affect the state’s economy or cause a surge in DUI arrests. This evaluation provides evidence supporting the efficacy of lower BAC limits as a countermeasure to alcohol-impaired driving.

Key finding

Utah's reduction of the per se BAC limit to .05 resulted in significant reductions in crash rates, alcohol involvement, and fatalities without negatively impacting the state's economy or causing sharp increases in DUI arrests.

Methodology

dataset

Provenance

The full processing record for this entry. Every stage of this paper's journey through the pipeline is logged — what ran, with which tool and model, how many attempts it took, and when it last completed. Discovered via bulk_ingest_rosap on 2026-05-23 (6 acquisition events logged).

Summary generated by qwen3.6-27b-prismaquant on 2026-06-10; verification: verified.

Topics

Ranked by relevance to this paper. Hover a topic for its definition.

• alcohol

Information type

What kind of knowledge this paper contributes, grouped by family — independent of topic (what it is about) and method (how it was studied).

• Empirical Findings: crash risk outcomes