Overview
Every day, about 34 people in the United States die in drunk-driving crashes — that's one person every 42 minutes. In 2023, 12,429 people died in alcohol-impaired driving traffic deaths. These deaths were all preventable.
How alcohol affects driving ability
Alcohol is a substance that reduces the function of the brain, impairing thinking, reasoning and muscle coordination. All these abilities are essential to operating a vehicle safely.
As alcohol levels rise in a person’s system, the negative effects on the central nervous system increase. Alcohol is absorbed directly through the walls of the stomach and small intestine. Then it passes into the bloodstream where it accumulates until it is metabolized by the liver. A person's alcohol level is measured by the weight of the alcohol in a certain volume of blood. This is called Blood Alcohol Concentration, or BAC. At a BAC of .08 grams of alcohol per deciliter (g/dL) of blood, crash risk increases exponentially. Because of this risk, it’s illegal in all 50 states, the District of Columbia and Puerto Rico to drive with a BAC of .08 or higher, except in Utah where the BAC limit is .05.
However, even a small amount of alcohol can affect driving ability. In 2023, there were 2,117 people killed in alcohol-related crashes where a driver had a BAC of .01 to .07 g/dL.
BAC is measured with a breathalyzer, a device that measures the amount of alcohol in a driver’s breath, or by a blood test.
The Effects of Blood Alcohol Concentration
| Blood Alcohol Concentration (BAC) in g/dL | Typical Effects | Predictable Effects on Driving |
|---|---|---|
| .02 | 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 | 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 | 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 | Clear deterioration of reaction time and control, slurred speech, poor coordination, and slowed thinking | Reduced ability to maintain lane position and brake appropriately |
| .15 | 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 |
Frequently Asked Questions
No. A drink is a drink.
A standard drink equals about half an ounce of alcohol (.54 ounces, to be exact). This is the approximate amount of alcohol found in:
- one shot of distilled spirits, or
- one 5-ounce glass of wine, or
- one 12-ounce beer.
How fast a person’s BAC rises varies based on a number of factors:
- The number of drinks. The more you drink, the higher your BAC.
- How fast you drink. When alcohol is consumed quickly, you will reach a higher BAC than when it is consumed over a longer period of time.
- Your sex. Women generally have less water and more body fat per pound of body weight than men. Alcohol does not go into fat cells as easily as other cells, so more alcohol remains in the blood of women.
- Your weight. The more you weigh, the more water is present in your body. This water dilutes the alcohol and lowers the BAC.
- Food in your stomach. Absorption will be slowed if you’ve had something to eat.
Because of the number of factors that affect BAC, it is very difficult to assess your own BAC or impairment. Even small amounts of alcohol affect one’s brain and the ability to drive. People often think they are “fine” after several drinks – but in fact, the failure to recognize alcohol impairment is often a symptom of impairment.
While the lower stages of alcohol impairment are undetectable to others, the drinker knows vaguely when the “buzz” begins. A person will likely be too impaired to drive before looking – or maybe even feeling “drunk.”
Know that alcohol steadily decreases a person’s ability to drive a motor vehicle safely. The more you drink, the greater the effect. As with BAC, the signs of impairment differ with the individual.
Drivers with a BAC of .08 are approximately 4 times more likely to crash than drivers with a BAC of zero. At a BAC of .15, drivers are at least 12 times more likely to crash than drivers with a BAC of zero. The risk of crashing is even greater for young males.
Risk Factors
Driving After Drinking
Driving after drinking is deadly. Yet it still continues to happen across the United States. If you drive while impaired, you could get arrested, or worse — be involved in a traffic crash that causes serious injury or death.
About 30% of all traffic crash fatalities in the United States involve drunk drivers (with BACs of .08 g/dL or higher). In 2023, there were 12,429 people killed in these preventable crashes. In fact, on average over the 10-year period from 2014-2023, about 11,000 people died every year in drunk-driving crashes.
In every state, it’s illegal to drive drunk, yet one person was killed in a drunk-driving crash every 42 minutes in the United States in 2023.
Car crashes are a leading cause of death for teens, and almost a third of young drivers killed in fatal crashes involved underage drinking. In 2023, 30% of young drivers 15 to 20 years old who were killed in crashes had BACs of .01 g/dL or higher.
To reduce alcohol-related fatal crashes among youth, all states have adopted a minimum legal drinking age of 21. NHTSA estimates that minimum-drinking-age laws have saved 31,959 lives from 1975 to 2017.
In 2023, the highest percentage of drunk drivers (with BACs of .08 g/dL or higher) were the 21-to 24-year-old age group. Men are most likely to be involved in this type of crash, with four male drunk drivers for every female drunk driver.
In 2023, 6,335 people operating a motorcycle were killed in traffic crashes. Of those motorcycle riders, 1,668 (26%) were drunk (BAC of .08 g/dL or higher).
Motorcycle operators involved in fatal crashes were found to have the highest percentage (26%) of alcohol-impaired drivers than any other vehicle types.
The 35-to-39 and 45-to-49 age groups had the highest percent, 34% each, of drunk motorcycle riders killed in 2023.
Repeat offenders who drink and drive are a very real, very deadly problem. Drivers with BACs of .08 g/dL or higher involved in fatal crashes were 6 times more likely to have prior convictions for driving while impaired than were drivers with no alcohol (6% and 1%, respectively).
When it comes to drunk driving, it affects more than just the driver. In 2023, among children (14 and younger) killed in motor vehicle crashes, 25% were killed in drunk-driving crashes. Of those deaths, more than half the time (52%) the child killed was in the vehicle driven by the drunk driver.
In addition to the human toll drunk driving takes on our country, the financial impact is devastating: based on 2019 numbers, impaired-driving crashes cost the United States $68.9 billion annually.
Consequences
Know the Facts Interactions between alcohol and other substances in the body such as certain medications or illegal drugs increase impairment and make driving more risky. Also see Drug-Impaired Driving
Driving a vehicle while impaired is a dangerous crime. Tough enforcement of drunk-driving laws has been a major factor in reducing drunk-driving deaths since the 1980s. Charges range from misdemeanors to felony offenses, and penalties for impaired driving can include driver’s license revocation, fines, and jail time. It’s also extremely expensive. A first-time offense can cost the driver upwards of $10,000 in fines and legal fees.
Many states require offenders to install ignition interlock devices at the driver’s own expense. An ignition interlock device is a breath test device connected to a vehicle’s ignition. The vehicle cannot be operated unless the driver blows into the interlock and has a BAC below a pre-set low limit, usually .02 g/dL. NHTSA strongly supports the expansion of ignition interlocks as a proven technology that keeps drunk drivers from getting behind the wheel.
Responsible behavior
BEING A RESPONSIBLE DRIVER IS SIMPLE: IF YOU ARE DRINKING, DO NOT DRIVE.
- Plan your safe ride home before you start the party, choose a non-drinking friend as a designated driver.
- If someone you know has been drinking, do not let that person get behind the wheel. Take their keys and help them arrange a sober ride home.
- If you drink, do not drive for any reason. Call a taxi, a ride-hailing service, or a sober friend.
- If you’re hosting a party where alcohol will be served, make sure all guests leave with a sober driver.
- Always wear your seat belt — it’s your best defense against impaired drivers.
If you see an impaired driver on the road, contact local law enforcement. Your actions could help save someone’s life.
NHTSA is dedicated to eliminating risky behaviors on our nation's roads
NHTSA demonstrates its commitment to eliminating drunk driving through research, public awareness campaigns, and state safety grant programs. We will continue until there are zero drunk-driving crashes on our roadways.