Blood alcohol concentration laws
Blood alcohol concentration (BAC) laws set legal limits for the percent of alcohol in a drivers’ blood. In the U.S., lower BAC limits are set for drivers under the legal drinking age. In other countries, lower levels often apply to all newly licensed drivers or newly licensed drivers under a specified age1. High BAC levels have a detrimental effect on drivers’ physical and cognitive abilities, including muscle coordination, speed control, and perception2.
What could this strategy improve?
Expected Benefits
Our evidence rating is based on the likelihood of achieving these outcomes:
Reduced alcohol-related crashes
Reduced fatal and non-fatal injuries
Potential Benefits
Our evidence rating is not based on these outcomes, but these benefits may also be possible:
Reduced underage drinking
What does the research say about effectiveness?
There is strong evidence that 0.08% blood alcohol concentration (BAC) laws reduce alcohol-related motor vehicle crashes and fatalities compared to higher BAC levels1, 3, 4, 5, 6. Setting lower BAC limits between 0.00 to 0.02% for young or inexperienced drivers has also been shown to reduce crashes and fatalities1, 7, 8 and reduce youth binge drinking9.
Lowering BAC limits from 0.10% to 0.08% reduced drunk-driving fatal crashes by 10.4% and saved 24,868 lives from 1983 to 20144. They also appear to be associated with increases in arrests due to driving under the influence (DUI)10. Reducing BAC limits further (e.g., from 0.08% to 0.05%) can result in greater reductions in alcohol-related crashes, injuries, and fatalities5, 6, 11, 12. BAC laws appear to be associated with lower levels of drinking among women of reproductive age13. Zero-tolerance laws for drivers under age 21 can lead to improved mental health and employment outcomes in adulthood while reducing the cost of alcohol-related harms to U.S. society9.
The effects of BAC laws appear to have slightly decreased since they were first enacted. Experts suggest it is likely because media campaigns and enforcement contributed to their effectiveness when they were first enacted, suggesting enforcement and awareness of BAC limits is important for sustained effectiveness3. Additionally, available evidence suggests the adoption of a 0.08% BAC limit is associated with an increase in hit-and-run crash fatalities. This may be partially due to a mismatch of penalties for DUI versus non-DUI hit-and-run arrests, a legal loophole state legislatures can address14. A cost-analysis of alcohol control strategies finds that the enactment and enforcement of BAC laws is cost-effective; the range of cost-effectiveness is $1,500 to $3,00015.
How could this strategy advance health equity? This strategy is rated inconclusive impact on disparities.
It is unclear what impact blood alcohol concentration laws may have on disparities in alcohol consumption and alcohol-related harms.
Blacks and Latinos experience disproportionate personal and social consequences of alcohol use, including alcohol use disorder symptoms and various social problems, compared with other racial and ethnic groups when consuming similar levels of alcohol18. For example, in 2018 6.4% of non-Hispanic white adults engaged in heavy drinking compared to non-Hispanic Black (2.9%), Hispanic (2.6%), and non-Hispanic Asian (2.0%) adults19. However, alcohol consumers who are Black or Hispanic appear more likely to experience alcohol-related injuries, accidents, and health and social consequences than consumers who are white. These racial and ethnic disparities are seen across all levels of consumption and may be most pronounced at low levels of consumption, suggesting there are environmental and cultural factors at play20, 21. Evidence suggests that the combined effects of drinking cultures, historically rooted patterns of racial discrimination and persistent socioeconomic disadvantage in racialized groups contribute to these disparities22.
What is the relevant historical background?
Alcohol is deeply rooted in American life and history. Prior to the American Revolution, alcohol was perceived as an invigorating and restorative beverage that did not spoil easily and was safer than water. Its taxation provided a major source of revenue for colonial governments23. After the American Revolution, the temperance and women’s rights movements shifted societal perspectives of alcohol and led efforts for its banishment. These efforts led to the adoption of the 18th Amendment in 1920, which banned the manufacture, sale, and transport of alcohol across the U.S., also known as Prohibition24. Prohibition ended in 1933 in large part because of the need to generate tax revenue and stimulate job growth during the Great Depression and gave states authority to regulate alcohol, and each have approached regulation differently23. Today, the federal government has limited authority to impose national-level rules and regulations and there continues to be a patchwork of alcohol regulations that vary by state. Some state legislatures have preempted local government from implementing certain regulations and laws25.
Throughout history, alcohol misuse was seen as a personal failing. This evolved over the 19th century as the addictive properties of alcohol were understood23. Alcohol use disorder is now seen as a chronic disease that is influenced by genetics, neighborhood disadvantage, stress, access to alcohol, drinking cultures and contexts, and alcohol-industry influences26, 27.
The first national effort to control alcohol-impaired driving began in the 1970s by the U.S. Department of Transportation (U.S. DOT) encouraging states to adopt a blood alcohol concentration (BAC) limit of 0.10% for intoxicated or impaired driving4. Later, national proponents and the U.S. DOT advocated for a 0.08% BAC limit, and from 1982 to 1997, most states and Washington D.C. adopted the new limit. This was partly due to the threat of regulatory action and loss of potential supplemental alcohol traffic-safety funding from U.S. Congress and the U.S. DOT. In 2000, the national standard for 0.08% BAC was put into federal law4.
Equity Considerations
- Has your community employed media campaigns to raise awareness about BAC limits and their enforcement? Are there opportunities to keep the media, community influencers, and policymakers informed about BAC laws and improve their effectiveness?
- Does your state have lower BAC limits for young and inexperienced drivers? Who can you partner with to advocate for such limits?
- What alternative transportation options are available in your community? Who can you partner with to incentivize alcohol consumers to utilize safe alternative transportation options?
Implementation Examples
As of January 2023, 49 states and Washington, D.C. have blood alcohol concentration (BAC) limits of 0.08% for drivers age 21 and over16. The state of Utah amendment to the BAC bill took effect on December 30th, 2018 and reduced the limit to 0.05% in the state16, 17.
Zero tolerance laws make it illegal for individuals under the age of 21 to drive with any measurable amount of alcohol in their systems; 14 states and Washington, D.C. have BAC limits of 0.00% for drivers under 21, two states have BAC limits of 0.01%, and 34 states have limits of 0.02%16.
Implementation Resources
‡ Resources with a focus on equity.
NHTSA-Drunk driving - National Highway Traffic Safety Administration (NHTSA). Drunk driving.
NTSB-DWI - National Transportation Safety Board (NTSB). Reaching zero: Actions to eliminate alcohol-impaired driving. Safety Report NTSB/SR-13/01. Washington, D.C.: NTSB; 2013.
Footnotes
* Journal subscription may be required for access.
1 CG-Motor vehicle injury - The Guide to Community Preventive Services (The Community Guide). Motor vehicle injury prevention.
2 NHTSA-Drunk driving - National Highway Traffic Safety Administration (NHTSA). Drunk driving.
3 Hosseinichimeh 2022 - Hosseinichimeh N, Williams R, MacDonald R, Li K, Vaca FE. What determines the success of states in reducing alcohol related crash fatalities? A longitudinal analysis of alcohol related crashes in the U.S. from 1985 to 2019. Accident Analysis and Prevention. 2022;174:106730.
4 Scherer 2019 - Scherer M, Fell JC. Effectiveness of lowering the blood alcohol concentration (BAC) limit for driving from 0.10 to 0.08 grams per deciliter in the United States. Traffic Injury Prevention. 2019;20(1):1-8.
5 Fell 2017b - Fell JC, Scherer M. Estimation of the potential effectiveness of lowering the blood alcohol concentration (BAC) limit for driving from 0.08 to 0.05 grams per deciliter in the United States. Alcoholism, Clinical and Experimental Research. 2017;41(12):2128-2139.
6 NICE-Killoran 2010 - Killoran A, Canning U, Doyle N, Sheppard L. Review of effectiveness of laws limiting blood alcohol concentration levels to reduce alcohol-related road injuries and deaths: Final report. London, UK: National Institute for Health and Care Excellence (NICE); 2010.
7 Fell 2016 - Fell JC, Scherer M, Thomas S, Voas RB. Assessing the impact of twenty underage drinking laws. Journal of Studies on Alcohol and Drugs. 2016;77(2):249-260.
8 Romano 2015 - Romano E, Scherer M, Fell J, Taylor E. A comprehensive examination of U.S. laws enacted to reduce alcohol-related crashes among underage drivers. Journal of Safety Research. 2015;55:213-221.
9 Abboud 2024 - Abboud T, Bellou A, Lewis J. The long-run impacts of adolescent drinking: Evidence from zero tolerance laws. Journal of Public Economics. 2024;231:105066.
10 Schwartz 2013 - Schwartz J, Davaran A. Enforcement following 0.08% BAC law change: Sex-specific consequences of changing arrest practices? Addictive Behaviors. 2013;38(10):2506-2512.
11 Fell 2014 - Fell JC, Voas RB. The effectiveness of a 0.05 blood alcohol concentration (BAC) limit for driving in the United States. Addiction. 2014;109(6):869-874.
12 Martin 2013 - Martin TL, Solbeck PAM, Mayers DJ, et al. A review of alcohol-impaired driving: The role of blood alcohol concentration and complexity of the driving task. Journal of Forensic Sciences. 2013;58(5):1238-1250.
13 Subbaraman 2023 - Subbaraman MS, Sesline K, Kerr WC, Roberts SCM. Associations between state-level general population alcohol policies and drinking outcomes among women of reproductive age: Results from 1984 to 2020 National Alcohol Surveys. Alcohol: Clinical and Experimental Research. 2023;47(9):1773-1782.
14 French 2024 - French MT, Gumus G. Hit-and-run or hit-and-stay? Unintended effects of a stricter BAC limit. Risk Analysis. 2024:1-18.
15 Chisholm 2018 - Chisholm D, Moro D, Bertram M, et al. Are the “best buys” for alcohol control still valid? An update on the comparative cost-effectiveness of alcohol control strategies at the global level. Journal of Studies on Alcohol and Drugs. 2018;79(4):514-522.
16 APIS - Alcohol Policy Information System (APIS). Welcome to the Alcohol Policy Information System.
17 UT BAC laws - State of Utah. H.B. 155 Driving under the influence and public safety: Revisions. 2017.
18 Mulia 2017 - Mulia N, Karriker-Jaffe KJ, Witbrodt J, et al. Racial/ethnic differences in 30-year trajectories of heavy drinking in a nationally representative U.S. sample. Drug and Alcohol Dependence. 2017;170:133-141.
19 CDC-Heavy Drinking 2018 - Boersma P, Villarroel M and Vahratian A. Heavy drinking among U.S. adults, 2018. National Center for Health Statistics; 2020.
20 Delker 2016 - Delker E, Brown Q, Hasin DS. Alcohol consumption in demographic subpopulations: An epidemiologic overview. Alcohol Research: Current Reviews. 2016;38(1):7-15.
21 Witbrodt 2014 - Witbrodt J, Mulia N, Zemore SE, Kerr WC. Racial/ethnic disparities in alcohol-related problems: Differences by gender and level of heavy drinking. Alcoholism: Clinical and Experimental Research. 2014;38(6):1662-1670.
22 Vaeth 2017 - Vaeth PAC, Wang-Schweig M, Caetano R. Drinking, alcohol use disorder, and treatment access and utilization among U.S. racial/ethnic groups. Alcoholism: Clinical and Experimental Research. 2017;41(1):6-19.
23 Olson 1985 - Olson S, Gerstein DR. Alcohol in America: Taking action to prevent abuse. Washington, D.C.: The National Academies Press; 1985.
24 Aaron 1981 - Aaron P, Musto D. Temperance and prohibition in America: A historical overview. In: Alcohol and public policy: Beyond the shadow of prohibition. Moore MH, Gerstein DR eds. Washington, D.C.: The National Academies Press; 1981.
25 APIS-State Preemption - Alcohol Policy Information System (APIS). About alcohol policy.
26 Zapolski 2014 - Zapolski TCB, Pedersen SL, McCarthy DM, Smith GT. Less drinking, yet more problems: Understanding African American drinking and related problems. Psychological Bulletin. 2014;140(1).
27 Sudhinaraset 2016 - Sudhinaraset M, Wigglesworth C, Takeuchi DT. Social and cultural contexts of alcohol use: Influences in a social–ecological framework. Alcohol Research: Current Reviews. 2016;38(1):35-45.
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