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Impaired Driving: Get the Facts

Every day, 28 people in the United States die in motor vehicle crashes that involve an alcohol-impaired driver. This amounts to one death every 53 minutes.1 The annual cost of alcohol-related crashes totals more than $44 billion.2

Thankfully, there are effective measures that can help prevent injuries and deaths from alcohol-impaired driving.

How big is the problem?

  • In 2014, 9,967 people were killed in alcohol-impaired driving crashes, accounting for nearly one-third (31%) of all traffic-related deaths in the United States.1
  • Of the 1,070 traffic deaths among children ages 0 to 14 years in 2014, 209 (19%) involved an alcohol-impaired driver.1
  • Of the 209 child passengers ages 14 and younger who died in alcohol-impaired driving crashes in 2014, over half (116) were riding in the vehicle with the alcohol-impaired driver.1
  • In 2014, over 1.1 million drivers were arrested for driving under the influence of alcohol or narcotics.3 That's one percent of the 121 million self-reported episodes of alcohol-impaired driving among U.S. adults each year.4
  • Drugs other than alcohol (legal and illegal) are involved in about 16% of motor vehicle crashes.5
  • Marijuana use is increasing6 and 13% of nighttime, weekend drivers have marijuana in their system.7
  • Marijuana users were about 25% more likely to be involved in a crash than drivers with no evidence of marijuana use, however other factors – such as age and gender – may account for the increased crash risk among marijuana users.5

A Closer Look - Terminology

Sobriety checkpoints: 

Traffic stops where law enforcement officers assess drivers’ level of alcohol impairment. These checkpoints consistently reduce alcohol-related crashes, typically by 9%.10

Ignition interlocks: 

Devices that are installed in the vehicles of people who have been convicted of driving while impaired. They prevent operation of the vehicle by anyone with a blood alcohol concentration (BAC) above a specified safe level (usually 0.02% – 0.04%). When installed, interlocks are associated with nearly a 70% reduction in re-arrest rates for impaired driving.11

Who is most at risk?

Young people:

  • At all levels of blood alcohol concentration (BAC), the risk of being involved in a crash is greater for young people than for older people.8
  • Among drivers with BAC levels of 0.08% or higher involved in fatal crashes in 2014, three out of every 10 were between 21 and 24 years of age (30%). The next two largest groups were ages 25 to 34 (29%) and 35 to 44 (24%).1

Motorcyclists:

  • Among motorcyclists killed in fatal crashes in 2014, 29% had BACs of 0.08% or greater.1
  • Motorcyclists ages 40-49 have the highest percentage of deaths with BACs of 0.08% or greater (40% in 2013).9

Drivers with prior driving while impaired (DWI) convictions:

  • Drivers with a BAC of 0.08% or higher involved in fatal crashes were seven times more likely to have a prior conviction for DWI than were drivers with no alcohol in their system. (7% and 1%, respectively).1

What are the effects of blood alcohol concentration (BAC)?

Information in this table shows the blood alcohol concentration (BAC) level at which the effect usually is first observed. 

Blood Alcohol Concentration (BAC)* Typical Effects Predictable Effects on Driving
.02%
About 2 alcoholic drinks**
  • Some loss of judgment
  • Relaxation
  • Slight body warmth
  • Altered mood
  • Decline in visual functions (rapid tracking of a moving target)
  • Decline in ability to perform two tasks at the same time (divided attention)
.05%
About 3 alcoholic drinks**
  • Exaggerated behavior
  • May have loss of small-muscle control (e.g., focusing your eyes)
  • Impaired judgment
  • Usually good feeling
  • Lowered alertness
  • Release of inhibition
  • Reduced coordination
  • Reduced ability to track moving objects
  • Difficulty steering
  • Reduced response to emergency driving situations
.08%
About 4 alcoholic drinks**
  • Muscle coordination becomes poor (e.g., balance, speech, vision, reaction time, and hearing)
  • Harder to detect danger
  • Judgment, self-control, reasoning, and memory are impaired
  • Concentration
  • Short-term memory loss
  • Speed control
  • Reduced information processing capability (e.g., signal detection, visual search)
  • Impaired perception
.10%
About 5 alcoholic drinks**
  • Clear deterioration of reaction time and control
  • Slurred speech, poor coordination, and slowed thinking
  • Reduced ability to maintain lane position and brake appropriately
.15%
About 7 alcoholic drinks**
  • Far less muscle control than normal
  • Vomiting may occur (unless this level is reached slowly or a person has developed a tolerance
    for alcohol)
  • Major loss of balance
  • Substantial impairment in vehicle control, attention to driving task, and in necessary visual and auditory information processing
*Blood Alcohol Concentration Measurement

The number of drinks listed represents the approximate amount of alcohol that a 160-pound man would need to drink in one hour to reach the listed BAC in each category.

**A Standard Drink Size in the United States

A standard drink is equal to 14.0 grams (0.6 ounces) of pure alcohol. Generally, this amount of pure alcohol is found in

  • 12-ounces of beer (5% alcohol content)
  • 8-ounces of malt liquor (7% alcohol content)
  • 5-ounces of wine (12% alcohol content)
  • 1.5-ounces or a “shot” of 80-proof (40% alcohol content) distilled spirits or liquor (e.g., gin, rum, vodka, whiskey)

Adapted from The ABCs of BAC, National Highway Traffic Safety Administration, 2005, and How to Control Your Drinking, WR Miller and RF Munoz, University of New Mexico, 1982.

How can deaths and injuries from impaired driving be prevented?

Effective measures include:

  • Actively enforcing existing 0.08% BAC laws, minimum legal drinking age laws, and zero tolerance laws for drivers younger than 21 years old in all states.4,10
  • Requiring ignition interlocks for all offenders, including first-time offenders 11
  • Using sobriety checkpoints.12
  • Putting health promotion efforts into practice that influence economic, organizational, policy, and school/community action.13,14
  • Using community-based approaches to alcohol control and DWI prevention.10,14,15
  • Requiring mandatory substance abuse assessment and treatment, if needed, for DWI offenders.16
  • Raising the unit price of alcohol by increasing taxes.17

Areas for continued research:

  • Reducing the illegal BAC threshold  to 0.05%.18-22
  • Mandatory blood alcohol testing when traffic crashes result in injury.23
  • Does marijuana impair driving? How and at what level?
  • Does marijuana use increase the risk of motor vehicle crashes?

What safety steps can individuals take?

Whenever your social plans involve alcohol and/or drugs, make plans so that you don’t have to drive while impaired. For example:

  • Before drinking, designate a non-drinking driver when with a group.
  • Don’t let your friends drive impaired.
  • If you have been drinking or using drugs, get a ride home or call a taxi.
  • If you’re hosting a party where alcohol will be served, remind your guests to plan ahead and designate their sober driver; offer alcohol-free beverages, and make sure all guests leave with a sober driver. 

Additional Data

References

  1. Department of Transportation (US), National Highway Traffic Safety Administration (NHTSA). Traffic Safety Facts 2014 data: alcohol-impaired driving. Washington, DC: NHTSA; 2015 [cited 2016 Feb 5]. Available at URL: http://www-nrd.nhtsa.dot.gov/Pubs/812231.pdf.
  2. Blincoe LJ, Miller TR, Zaloshnja E, Lawrence BA. The economic and societal impact of motor vehicle crashes, 2010. (Revised). Washington, DC: NHTSA; 2015. [cited 2016 Feb 5]. Available at URL: http://www-nrd.nhtsa.dot.gov/pubs/812013.pdf.
  3. Department of Justice (US), Federal Bureau of Investigation (FBI). Crime in the United States 2014: Uniform Crime Reports. Washington (DC): FBI; 2015 [cited 2016 Feb 5]. Available at URL https://www.fbi.gov/about-us/cjis/ucr/crime-in-the-u.s/2014/crime-in-the-u.s.-2014/tables/table-29.
  4. Jewett A, Shults RA, Banerjee T, Bergen G Alcohol-impaired driving among adults— United States, 2012. MMWR Morbi Mortal Wkly Rep. 2015;64(30):814-17.
  5. Compton RP, Berning A. Traffic Safety Facts Research Note: drugs and alcohol crash risk. Washington, DC: NHTSA; 2015 [cited 2016 Feb 5]. Available at URL: http://www.nhtsa.gov/staticfiles/nti/pdf/812117-Drug_and_Alcohol_Crash_Risk.pdf.
  6. Substance Abuse and Mental Health Administration. Cannabis. 2015 6/2/2015 [cited 2015 Jul 17]. Available at URL: http://www.samhsa.gov/atod/cannabis.
  7. Berning A, Compton R, Wochinger K. Results of the 2013–2014 National Roadside Survey of alcohol and drug use by drivers. Washington, DC: NHTSA; 2015 (DOT HS 812 118).
  8. Zador PL, Krawchuk SA, Voas RB. Alcohol-related relative risk of driver fatalities and driver involvement in fatal crashes in relation to driver age and gender: an update using 1996 data. Journal of Studies on Alcohol 2000;61:387-95.
  9. Department of Transportation (US), National Highway Traffic Safety Administration (NHTSA). Traffic Safety Facts 2013 data: motorcycles. Washington, DC: NHTSA; 2015 [cited 2016 Feb 5]. Available at http://www-nrd.nhtsa.dot.gov/Pubs/812148.pdf.
  10. Guide to Community Preventive Services. Motor vehicle-related injury prevention: reducing alcohol-impaired driving. [cited 2016 Feb 5]. Available at URL: http://www.thecommunityguide.org/mvoi/AID/index.html.
  11. Guide to Community Preventive Services. Reducing alcohol-impaired driving: ignition interlocks. [cited 2016 Feb 5]. Available at URL: http://www.thecommunityguide.org/mvoi/AID/ignitioninterlocks.html.
  12. Guide to Community Preventive Services. Reducing alcohol-impaired driving: publicized sobriety checkpoint programs. [cited 2016 Feb 5]. Available at URL: http://www.thecommunityguide.org/mvoi/AID/sobrietyckpts.html.
  13. Hingson R, Sleet DA. Modifying alcohol use to reduce motor vehicle injury. In Gielen AC, Sleet DA, DiClemente R (Eds). Injury and Violence Prevention: Behavior change Theories, Methods, and Applications. San Francisco, CA: Jossey-Bass, 2006.
  14. Holder HD, Gruenewald PJ, Ponicki WR, et al. Effect of community-based interventions on high-risk drinking and alcohol-related injuries. JAMA 2000;284:2341-7.
  15. Shults RA, Elder RW, Nichols J, et al. Effectiveness of multicomponent programs with community mobilization for reducing alcohol-impaired driving. Am J Prev Med 2009;37(4):360-371.
  16. Higgins-Biddle J, Dilonardo J. Alcohol and highway safety: screening and brief intervention for alcohol problems as a community approach to improving traffic safety. Washington, DC: NHTSA; 2013 DOT HS 811 836.
  17. Guide to Community Preventive Services. Reducing excessive alcohol use: increasing alcohol taxes. [cited 2016 Feb 5]. Available at URL: http://www.thecommunityguide.org/alcohol/increasingtaxes.html.
  18. Howat P, Sleet D, Smith I. Alcohol and driving: is the .05% blood alcohol concentration limit justified? Drug Alcohol Rev 1991;10(1):151-66.
  19. Wagenaar AC, Livingston MD, Staras SS. Effects of a 2009 Illinois alcohol tax increase on fatal motor vehicle crashes. Am J Public Health 2015;105(9):1880-5.
  20. Wagenaar AC, Maldonado-Molina MM, Ma L, et al. Effects of legal BAC limits on fatal crash involvement: analyses of 28 states from 1976 through 2002. J Safety Res 2007;38:493-9.
  21. Fell JC, Voas RB. The effectiveness of a 0.05 blood alcohol concentration (BAC) limit for driving in the United States. Addiction 2013;109:869-74.
  22. Blais E, Bellavance F, Marcil A, Carnis L. Effects of introducing an administrative .05% blood alcohol concentration limit on law enforcement patterns and alcohol-related collisions in Canada. Accid Anal Prev 2015;82:101-11.
  23. National Committee on Injury Prevention and Control. Injury prevention: meeting the challenge. New York, NY: Oxford University Press, 1989, p.124.
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