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Zero Tolerance Laws/Blood Alcohol Concentration


Zero-tolerance laws make it a criminal DUI offense for those under age 21 to drive with any detectable amount of alcohol in their system (Guide to Community Preventive Services, 2000). A blood alcohol concentration (BAC) from 0.00% to 0.02% is considered as zero, depending on the state. Even one glass of wine with dinner could lead to a DUI charge for a young driver.

BAC is a measure of the amount of alcohol in a person's bloodstream. Although BAC levels are commonly expressed in percent, state laws generally specify BAC levels as grams of alcohol per 100 milliliters of blood (abbreviated as grams per deciliter, g/dL).

Thirty-four states have BAC limits of 0.02, two have 0.01, and 15 states have 0.00 g/dL.

A per se impaired driving law indicates that drivers are considered intoxicated by the law if the BAC limit is exceeded and no additional proof of impairment is necessary to obtain a conviction. These laws pertain to drivers under age 21 of noncommercial cars, trucks, and motorcycles.

All 50 states and Washington D.C. have per se laws stating that it is a crime to drive with a BAC of .08 percent or higher for those of legal drinking age.

Penalties for underage drivers are strong if there is a mandatory administrative license sanction, followed by a discretionary one. The strongest law has an administrative license sanction for 91 days or longer, or at least 31 days. Somewhat strong is a mandatory criminal license sanction with a minimum of 91 days or longer. Less strong is a discretionary license sanction for as little as 31 days.

Hawai‘i law

According to the STOP Act report, 2015, Hawai‘i law has a BAC limit at or above 0.02 g/dL as per se (conclusive) evidence of a violation for drivers under age 21. (SAMHSA, 2015).

HRS §281-44a requires all licensed premises to post a sign in or about the premises...notifying all customers and others of possible sanctions that may be imposed for operating a vehicle under the influence of an intoxicant…The sign shall be conspicuously positioned to be seen by an ordinarily observant person.

Discussion of effectiveness

Evidence provides strong support for the effectiveness of lower blood alcohol concentration limits for reducing the rate of drunk driving and alcohol-related crashes, fatalities, and injuries ( Fell & Voas, 2006).

The Community Preventive Services Task Force (2013) recommends the lower BAC for young or inexperienced drivers based on sufficient evidence of their effectiveness in reducing alcohol-related motor vehicle crashes: fatal crashes decreased by 24%, 17%, and 9% (3 studies); fatal and nonfatal injury crashes decreased by 17% and 4% (2 studies); crashes in which the investigating police officer believed that the driver had been drinking alcohol decreased by 11% (1 study).

The zero tolerance law for those under age 21 was associated with a 2.9% decrease (statistically significant) in FARS ratios, which accounts for saving an estimated 102 lives nationally per year (Fell, Scherer, Thomas, & Voas, 2016). These results were based on structural equation modeling of predictors on the outcome of FARS vehicular crash death ratios of drinking to non-drinking drivers under age 21.

The law for zero tolerance BAC was associated with a 4.7% decrease in beer consumption based on a structural equation modeling study (Fell, Scherer, Thomas, & Voas, 2016).

The Institute of Medicine (2014) recommended enforcement of zero tolerance laws as well as media campaigns to increase young people’s awareness of BAC limits and enforcement efforts and the consequences of violation.

Causal Domain

Economic availability
Not applicable
Retail availability
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Social availability
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Promotion & media
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Community norms
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Discussion of effectiveness

Summary Indicator:
Effective based on Cochrane Review or Community Guide or NREPP
Indicator of effectiveness:
Not effective
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Not applicable
Varied evidence of effectiveness
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Not applicable
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Strength of evidence:
No evidence found
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Not applicable
Grey literature
16% filled pie chart
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Single published study
33% filled pie chart
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Numerous published studies
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Systematic review, meta-analysis
83% filled pie chart
Not applicable
Cochrane Review, Community Guide, NREPP
100% filled pie chart

Implementation in Hawai‘i

Time Period
Zero Tolerance Laws/Blood Alcohol Concentration
2022 - Present
Hawai‘i Alliance For Drug-Free Communities (Statewide)



References for description of strategy

Evidence base

  • Fell, J. C., Scherer, M., Thomas, S., & Voas, R. B. (2016). Assessing the impact of twenty underage drinking laws.Journal of Studies on Alcohol and Drugs,(2), 249-260.
  • Fell, J. C., & Voas, R. B. (2006). The effectiveness of reducing illegal blood alcohol concentration (BAC) limits for driving: evidence for lowering the limit to. 05 BAC. Journal of Safety Research, 37(3), 233-243.
  • Guide to Community Preventive Services. (2013, September 23). Reducing alcohol-impaired driving: lower BAC laws for young or inexperienced drivers. Retrieved from:
  • Wagenaar, A. C., Maldonado-Molina, M. M., Ma, L., Tobler, A. L., & Komro, K. A. (2007). Effects of legal BAC limits on fatal crash involvement: analyses of 28 states from 1976 through 2002. Journal of Safety Research, 38(5), 493-499.
  • Wagenaar, A. C., O'Malley, P. M., & LaFond, C. (2001). Lowered legal blood alcohol limits for young drivers: effects on drinking, driving, and driving-after-drinking behaviors in 30 states. American Journal of Public Health, 91(5), 801.

Further reading