Blood Alcohol Concentration Limits

Our Thinking

Maximum legal BAC limits vary around the world, as do countries’ and communities’ commitments to (1) promoting public education about BAC limits, (2) consistent and effective enforcement of legal BAC limits, and (3) punishments for drivers whose BAC levels are found to be above the legal limit.

Research consistently shows that compliance with—and enforcement of—BAC limits helps to reduce the number of accidents caused by impaired drivers. For legislated BAC limits to effectively help reduce the number of accidents and injuries caused by alcohol-impaired drivers, a key factor is the commitment of governments and communities to public education, compliance, and enforcement.

In addition to education and prevention efforts, certain approaches have demonstrated sufficient levels of success for broad legislative adoption in the United States—namely, Administrative License Revocation, ignition interlocks for offenders, and stiffer penalties for repeat offenders and offenders with higher BAC levels.

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In all jurisdictions, the establishment of clearly defined legal BAC levels of at least .08 g/dl

Sound scientific research shows that 0.08 is the level at which virtually every driver is impaired – affecting all of the critical driving skills including braking, steering, judgment, and response time.

The establishment of zero-tolerance BAC levels for drivers who are under the legal drinking age
DUI Courts with an approach that combines conviction with court-ordered treatment, frequent alcohol testing, and close community supervision

This cooperative approach involves all criminal justice stakeholders (prosecutors, defense attorneys, judges, probation officers, law enforcement) and is designed to protect public safety by addressing the root causes of hardcore drunk driving.


Effective use of IIDs requires proper assessment and treatment, supervision, and verification of installation for all offenders ordered to install the device.

Evidence shows interlocks are highly effective in preventing alcohol-impaired driving for both hardcore offenders and first-time offenders while they are installed. We believe actions must be taken to improve ignition interlock installation rates and to expand treatment opportunities. Research shows this is particularly important for hardcore drunk drivers who are resistant to changing their behavior.

It is essential that an effective screening for alcohol, drugs, and mental health issues be conducted with DUI offenders in tandem with an interlock sanction to identify offenders who are likely to recidivate and are in need of treatment. Research shows that repeat DWI offenders often suffer from multiple disorders. In one study, in addition to a lifetime alcohol disorder, 41% of the participants had a drug-related disorder and 44% had a major mental health disorder that was not alcohol or drug-related (Shaffer et al., 2007). Without this critical step, long-term behavior change for these offenders and long-term reduction in drunk driving death and injury are unlikely.

For third-time offenders found guilty of driving while intoxicated, a mandatory felony trial—and felony sentencing if the offender is found guilty

In addition, for repeat offenders, we support court-ordered treatment for alcohol abuse (not as a substitute for penalties, but in addition to other sanctions).

The implementation of Administrative License Revocation (immediate revocation of a driver’s license upon arrest for drunk driving)—and adoption of ALR in all jurisdictions

We endorse ALR as a swift and highly effective means of getting drunk drivers off the roads.

Consistent enforcement of BAC limits
  • We encourage the use of measures ranging from breath testing to testing in hospital emergency rooms following accidents in which alcohol may be involved.
  • We also support robust police training with regard to BAC enforcement, and the reallocation of adequate resources to effectively enforce BAC legislation.
Improved judicial training

Impaired driving offenses involve a distinct set of concerns with regard to law enforcement procedures, BAC levels, the details of BAC testing, etc. Officers of local courts should be provided with training which addresses these details.

Increased promotion of public education about BAC limits and the dangers of drunk driving
  • We encourage a coordination of initiatives to promote education about legal BAC limits through the engagement of a broad range of partners, including government authorities, police, the hospitality industry, advocacy groups, industry groups, community groups, and schools.
  • Such initiatives should address what certain BAC levels mean for individuals in terms of the number of drinks consumed, the dangers of drunk driving, and the consequences and penalties for drivers whose BAC levels exceed legal limits.
  • This is a particularly critical topic because of the high rates of alcohol-related traffic deaths every year around the world. From a policy perspective, issues related to BAC limits tend to focus on disparities amongst legal limits, inconsistent or ineffective enforcement of limits, and the relationship of BAC limits to harmful behaviors associated with alcohol abuse—chief among them, impaired driving and its often tragic consequences.


    Alcohol consumption is known to affect an individual’s motor skills, and to slow an individual’s reaction time when performing a precision activity such as driving a motor vehicle1. The impairments that result when a driver is intoxicated range from slowed reflexes to blurred vision and poor judgment of distance, speed, and possible hazards. The reaction time of a drunk driver, compared to a sober driver, can be reduced by up to 30 percent2.

    It is well-documented that a driver’s risk of being involved in a fatal traffic accident increases with the amount of alcohol consumed. Traffic accident statistics show a clearly escalating level of risk as BAC levels increase.


    Source: Federal Aviation Regulation (CFR) 91.17 commentary as reported at

    In the United States alone, alcohol-impaired traffic fatalities account for 29 percent of all traffic fatalities. On average, someone is killed in an alcohol-related traffic accident approximately every 50 minutes. In 2015, 10,265 people died in alcohol-related traffic crashes in the United States3.

    Deaths in crashes involving drunk drivers increased 3.2 percent in 2015.  According to NHTSA, the  majority of those crashes involved drivers with blood alcohol concentration of .15 or higher – nearly double the legal limit.  Americans have driven more during this period, yet the fatality rate per vehicle mile traveled (VMT) has declined steadily.  While the losses remain too high, alcohol-impaired driving fatalities in the U.S. have declined 51% from 1982 to 2015.




    The vast majority of jurisdictions worldwide attempt to minimize the harms caused by impaired driving by setting maximum legally permissible BAC levels for drivers. These maximum legal BAC levels range from .00 g/dl to .08 g/dl. (See Appendix I for a complete listing of BAC limits worldwide.) According to a WHO report published in 2011, of 133 countries:

    • 39 percent set the legal BAC limit at .05%;
    • 34  percent set the legal BAC limits at .08%; and
    • 10 percent have adopted zerotolerance policies, where no measurable BAC is permitted4.

    In addition to variations in BAC limits from country to country—including some nations with no governmentally-imposed BAC limit—research shows that countries vary in terms of the penalties they impose for violations of legal BAC limits, and the extent to which such limits are communicated and enforced.



    Source: International Center for Alcohol Policies, updated December 2010, and converted from mg/ml to mg/dL
    *BAC for professional drivers and drivers under 24 years of age is .00 mg/dl. **BAC for bus and truck drivers is .00 mg/dl. ***BAC for professional drivers is .02 mg/dl.


    Some countries impose a lower legal BAC limit for younger or less experienced drivers. The reasons vary and include the limited driving experience of young drivers, a tendency to overestimate their driving skills, and a general penchant for risk-taking behavior, such as speeding5. In some countries (e.g. Australia, Croatia, Puerto Rico, Spain, and the United States), lower BAC levels are set for younger or novice drivers6.

    More stringent BAC limits are also set by some jurisdictions for people who operate commercial vehicles, airline pilots, captains of ships, and people who drive vehicles such as taxis, trucks, and buses. In addition, in some countries, BAC limits extend beyond drivers of automobiles to operators of various types of other vehicles, including personal aircraft, snowmobiles, and even bicycles7.

    There is a body of research which identifies repeat drunk driving offenders and “hardcore” drunk drivers as a large and disproportionate source of highway crashes. As defined by The Foundation for Advancing Alcohol Responsibility ( and the National Hardcore Drunk Driver project in the United States as well as other organizations and government entities, a hardcore drunk driver is someone who (1) drives with a BAC level of .15 g/dl or above and/or (2) drives repeatedly while intoxicated (e.g., as demonstrated by having more than one arrest for doing so)8. For example, in the United States, as many as 70 percent of all drunk driving fatalities are attributed to hardcore drunk drivers.  Drivers with BAC levels in excess of .15 are estimated to be only one percent of all drivers on weekend nights; however, they are involved in nearly 50% of all fatal crashes during that time9.

    Additionally, there is growing public awareness about the dangers of driving after drinking when in a so-called “buzzed” state (meaning at or just above the legal BAC limit) versus being overtly drunk. Recent advocacy campaigns addressing this phenomenon include the Ad Council’s “Buzzed Driving is Drunk Driving” campaign10.

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    Measures have been instituted by jurisdictions worldwide in an attempt to reduce the incidence of alcohol-related traffic accidents and to prevent those who are intoxicated from driving. In the United States, all 50 states and the District of Columbia have passed legislation establishing that a driver with a BAC of .08 g/dl is considered legally intoxicated. In addition, 48 states and the District of Columbia have laws and penalties targeted at those who drive with elevated or “high” BAC levels, generally .15 g/dl1.

    In the European Union, where 25 percent of the annual traffic fatalities are alcohol-related, the European Commission’s adopted platform for reducing alcohol-related harm includes reducing injuries and deaths from alcohol-related road accidents. The effort, which seeks to reduce the number of fatal accidents by 50 percent by 2020, calls for a zero BAC limit for new drivers, as well as for professional commercial vehicle drivers and bus drivers2.


    DUI Courts (sometimes called DWI Courts) deal with hardcore drunk driving offenders by providing long-term accountability and rehabilitation in addition to conviction. The DUI Court model was first implemented on a trial basis in the U.S. in the 1990s, and is designed to protect public safety by addressing the root causes of repeat DUI offenders and hardcore drunk drivers. This entails a cooperative approach involving all criminal justice stakeholders (prosecutors, defense attorneys, judges, probation officers, law enforcement). In addition to being convicted, offenders typically enter into court-ordered treatment, undergo frequent alcohol testing, and are under close community supervision. Recent research results show that a Georgia program funded by NHTSA and the DOJ is credited with reducing recidivism by 38 to 65 percent, compared to other programs in state3.


    In addition to penalties which involve the revocation of driving privileges following a conviction for driving while intoxicated, Administrative License Revocation (ALR) involves the immediate revocation of a driver’s license when he or she is arrested for driving while intoxicated. Typically, this type of license suspension is implemented if (1) the driver refuses a BAC breath test but the law enforcement officer on hand deems there is cause for arrest based on impairment; or (2) if a breath test is administered and reflects a BAC level above the legal limit. Advocates of ALR promote the practice as a rapid and effective response which helps to keep the roads safe for other drivers. Currently in the U.S., 42 states and the District of Columbia have laws allowing for Administrative License Revocation4.


    Although the majority of nations have established legal BAC limits, levels of public education and government enforcement vary greatly. Yet research suggests that factors such as increased education and information about BAC limits and the dangers of driving while impaired can play a key role in enhancing the effectiveness of legislation which targets drunk driving5. Public education campaigns to promote understanding of BAC limits—whether implemented through governments, local communities, advocacy groups, and/or the beverage alcohol industry—have demonstrated positive results6.


    Consistent and visible enforcement has been shown to be a powerful deterrent to impaired driving. Enforcement methods which have proven effective include breath testing (random or where impairment of a driver is suspected), sobriety checkpoints, police patrols, and officer training7. However, 30 percent of countries do not use random breath tests to enforce BAC limits. Of the 141 countries reporting on random breath testing of drivers, 71 did some type of testing, 24 did random breath testing only at roadside checkpoints, and 16 used special mobile units8.

    Punishment for convicted drunk drivers also varies a great deal from country to country, and in some jurisdictions, is linked to the extent to which an offender’s BAC level exceeds the legal limit. Generally speaking, the consequences for exceeding legally imposed BAC limits range from mandatory educational programs and monetary fines to more severe measures such as automatic license suspension and prison sentences9.


    Ignition Interlock devices—BAC breath testing devices linked to a vehicle’s ignition system—require that a driver take a breath test before being allowed to start the vehicle’s engine. The vehicle will not start unless the driver’s BAC is below a pre-set level, and the interlock system tracks each attempt to start the vehicle. In addition, interlock devices can be calibrated for “rolling re-tests” which require a driver to provide breath tests at regular intervals—thus preventing drivers from circumventing the device by asking a sober friend to start the car, drinking while driving, leaving the car idling while going into a bar to drink, etc10.

    According to the National Conference on State Legislatures, all fifty states have some sort of ignition interlock law. Fourteen states—Alaska, Arizona, Arkansas, Connecticut, Hawaii, Kansas, Louisiana, Nebraska, New Mexico, New York, Oregon, Utah, Virginia, and Washington—have mandatory ignition interlock provisions for all offenses. Illinois and Colorado’s laws are not mandatory for a first conviction, but there are strong incentives to install an interlock device on the first conviction11.


    In addition to ignition interlocks, other advanced sensor technologies for alcohol detection are under development. Reasons cited for the research has stemmed from some concerns about the limitations of ignition interlock devices currently on the market. Interlocks target convicted offenders with any measurable amount of blood alcohol. They also require frequent re-tests by drivers that would be too intrusive for widespread use by the general public.


    The Automotive Coalition for Traffic Safety (ACTS) and the National Highway Traffic Safety Administration are engaged in a cooperate research agreement. The DADSS program, or Driver Alcohol Detection System for Safety, aims to research, develop and demonstrate non-invasive in-vehicle alcohol detection technologies that can measure a driver’s BAC12.

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