[Infographic] Drunk Driving: The Leading Cause of Death on U.S. Roads

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One in every three fatal road crashes in the U.S. is caused by alcohol-impaired driving. Every 48 minutes, one person dies from a drunk driving accident. This number includes not only intoxicated drivers, but also the passengers of other vehicles who become their innocent victims. That’s 30 people a day–a total of almost 11,000 Americans a year.

Aside from fatalities, drunk driving incidents are also responsible for serious injuries. Every two minutes, one person is injured due to alcohol-impaired driving. According to the National Highway Traffic Safety Administration (NHTSA), two out of three Americans will be involved in a drunk driving crash in their lifetime.

Although there’s been a downward trend in the number of drunk driving incidents these past two decades, the total number of drunk driving deaths per year remains too high for something that is completely preventable. To bring these devastating numbers down, it’s important for us to understand why these accidents still happen and what we can do to prevent them.

Even small amounts of alcohol can affect your ability to safely operate a motor vehicle.

What happens when you drink alcohol?

Alcohol is directly absorbed by the stomach and the small intestine. It is then absorbed into the bloodstream, which allows it to travel to other parts of the body, including the brain. It takes around 30 to 70 minutes for alcohol to be absorbed and measured.

Even small amounts of alcohol can affect your ability to safely operate a motor vehicle. People often say they feel fine after a few drinks. However, failure to admit that you’re buzzed is already a sign of alcohol impairment. On your own, it’s extremely difficult to assess whether or not you are fit to drive.

What counts as alcohol-impaired driving?

Legally, a driver’s level of impairment is measured by blood alcohol concentration (BAC). This measurement refers to the weight of ethyl alcohol or ethanol in a certain volume of blood.

This can be measured by testing your breath via a device called a breathalyzer, or by testing your blood or urine. A reading of .10% BAC means that your bloodstream contains one part alcohol for every 1,000 parts of blood.

In all states (except for Utah) and the District of Columbia, operating a vehicle with a blood alcohol concentration of 0.08% is considered impaired driving. In Utah, stricter limits were recently enforced, lowering the limit to 0.05%. People younger than 21 years of age may also be arrested for driving while intoxicated with a BAC under the adult limit.

What happens when you drink and drive?

The number of drinks it takes for a person’s BAC to reach the legal limit depends on several factors, including sex, height, and weight. For a general idea of what happens when you drink and drive, we’ll use the average heights and weights of an American male and female.

For illustration purposes, one drink is equivalent to any of the following:

For an average American male who weighs 200 lb. and is at least 5’9 tall:

After 1 drink – 0.02% BAC

Light and moderate alcohol drinkers will feel more relaxed and experience elevated moods. At the same time, multi-tasking and tracking moving objects start to require more focus.

After 2 drinks – 0.04% BAC

Mild impairment begins at this stage. You will begin to exhibit slowed speech and difficulty with balance or coordination. You may start to feel less inhibited and begin showing exaggerated behavior. Sleepiness will also begin to set in. At this point, your driving skills will be significantly affected.

After four drinks, a driver may find it difficult to concentrate and control vehicle speed. A lack of inhibition can lead to impaired judgment when it comes to avoiding and reacting to road hazards.

After 3 drinks – 0.06 % BAC

The sense of relaxation may soon be replaced by feelings of aggression. Speech and memory functions are further impaired. There is also a significant loss of small muscle control, particularly in the eyes. This will cause drivers to have difficulty steering and focusing on the road.

After 4 drinks – 0.08% BAC (Legal limit in most states)

At this stage, you may find it difficult to concentrate and control vehicle speed. A lack of inhibition can lead to impaired judgment when it comes to avoiding and reacting to road hazards. Cognitive processes are also impaired, resulting in short-term memory loss and reduced capability of following signals.

After 5 or more drinks – 0.09% BAC and higher

Once you go above the legal blood alcohol limit, your ability to drive safely becomes severely compromised. This stage is characterized by slurred speech and slowed thinking. Your reaction time, attention, and muscle coordination will deteriorate. Processing visual and auditory cues will be substantially impaired.

Simple tasks like staying in your lane, applying brakes as needed, and controlling your vehicle will become extremely difficult.

For an average American female who weighs 170 lb. and is at least 5’4 tall:

After 1 drink – 0.03% BAC

You will start to experience reduced muscle control and coordination. Speech, attention, and memory impairment should be expected. You will begin to feel drowsy and may start exhibiting exaggerated motions and emotions.

After 2 drinks – 0.05% BAC

You will begin to feel more confident and less inhibited. Vision and hearing impairment will begin to set in. Slowed speech, shorter attention span, and coordination difficulties become more apparent.

After 3 drinks – 0.08% BAC (Legal limit in most states)

Once you have reached the legal limit, you will notice that your reaction time has slowed down, making it extremely dangerous to drive. Your depth perception will also be off, making it unsafe to navigate through traffic.

After 4 drinks and up – 0.10% BAC and higher

At this point, you will be slurring your words and your vision will become blurry. You will feel out of balance and have obvious problems controlling your movements. It is illegal and extremely unsafe to operate a vehicle.

Factors that may affect a person’s level of intoxication

Aside from the number of alcoholic drinks you consume, there are several factors that may speed up the rate of absorption of alcohol in your system. Here are some of the things that can make your BAC rise faster than other people.

Biological sex

Alcohol is metabolized differently in women’s bodies compared to men due to the difference in their body composition. Females have more body fat than males, which slows down alcohol absorption and keeps it in the bloodstream for a longer period. At the same time, females also have fewer enzymes for metabolizing alcohol.


Your weight also determines the rate at which alcohol is diffused in your body. Someone heavier will have a lower blood alcohol concentration compared to a lighter person drinking the same number of drinks.


Prescription drugs and over-the-counter medications may have dangerous interactions with alcohol. Be sure to read the labels on your medications and ask your doctor about possible interactions before you drink alcohol. Better yet, it’s advisable to avoid alcoholic drinks altogether while you’re taking medication.

Food intake

The amount of food you eat before drinking alcohol can also affect how quickly you get intoxicated. Drinking on an empty stomach will irritate your digestive system and accelerate alcohol absorption. Eating protein-rich food like meat and dairy products can slow down the effect of alcohol in your system.

Existing health conditions

Some people simply have difficulty metabolizing alcohol. This could be caused by enzyme deficiencies or other pre-existing health conditions that limit the body’s ability to process alcohol.

Rate of alcohol consumption

Chugging beer or downing shots in a short amount of time will get you intoxicated faster. Failing to pace your drinks overwhelms your digestive system, reducing its capability of metabolizing alcohol. It is better to pace yourself and space out your drinks over a longer period of time.

Police officers may assess your ability to drive through a field sobriety test. The Standard Field Sobriety Test (or SFST) is comprised of three tests that are scientifically proven to determine legal intoxication.

The Standard Field Sobriety Test

Police officers may assess your ability to drive through a field sobriety test. The Standard Field Sobriety Test or SFST is comprised of three tests that are scientifically proven to determine legal intoxication. The result of a sobriety test is admissible as evidence in court.

The SFST includes a test for horizontal gaze nystagmus (involuntary “jerking” of the eyeball), a walk-and-turn test, and a one-leg stand test. These tests are meant to assess your balance, coordination, and ability to multi-task while on the road.

How to prevent drunk driving accidents

Being a responsible driver and encouraging others to do so as well can help prevent drunk driving accidents. By following these tips, we can all do our part in reducing the number of drunk driving deaths per year:

Prepare non-alcoholic drinks

If you’re hosting a party for friends or family, it’s a good idea to prepare non-alcoholic drinks for your guests. This will help ease some of the pressures of social drinking and give people the option to stay sober, especially if they’re driving home.

Teach your kids about responsible alcohol consumption

Based on drunk driving statistics, about 10% of all alcohol-impaired crashes involve teens who engage in underage drinking. To help prevent these incidents, it’s best to talk to your kids about how to deal with the social pressures of drinking at a young age. You should also set a good example and make sure they understand the real-life consequences of drunk driving.

Plan a safe way of getting home

If you and your friends are planning to drink, it’s best to sort out your ride situation first. You can choose to have a designated driver who will stay sober, or you can leave your cars behind and call a cab or use a ride-sharing service instead. Whatever you choose, be sure to plan your transportation options ahead of time so you can have a safe night out.

Look out for your friends

Don’t hesitate to step in if you notice someone consuming too much alcohol too fast. Take them aside to take a break from drinking and encourage them to sip some water or grab something to eat with you. Even if they don’t seem visibly drunk, don’t let them drive home.

Wait it out

Even if you only had a mild drink, you shouldn’t take any chances by operating your vehicle. On average, the human body can metabolize .01% to .02% BAC per hour. It helps to drink a lot of water between drinks and eat lots of protein-rich food.

The total number of hours you need to sober up will depend on several factors such as your sex, weight, and how many drinks you have. If you have a lot to drink, call a sober friend to take you home or consider staying the night to sleep it off.

If you and your friends are planning to drink, it’s best to sort out your ride situation first. One option is to choose a designated driver who will stay sober.

Buckle up

Aside from drinking responsibly, you and your passengers should always practice vehicle safety. Make sure all adults wear their seatbelts, and that children are safely strapped in their car seats or boosters. Doing so can help protect you and your loved ones from serious and fatal injuries in case you’re involved in a vehicle crash with a drunk driver.

Drunk Driving Infographic

Check out this infographic to learn everything you need to know about drunk driving. Click to view full size.
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