Updated on February 15, 2024
7 min read

Drinking & Driving: Risks, Examples of Consequences, & BAC Levels

Not only are there legal consequences for drunk driving, but you can injure yourself and others. Accidents involving drinking over the legal BAC can end in death.

In the U.S., almost 30 people die in drunk driving-related accidents every day.1

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Dangers & Risks of Drunk Driving

Drunk driving is extremely dangerous. Not only to the driver, but also to those on the road around the driver operating the vehicle. 

The risks of drunk driving and DUIs include, but are not limited to:

  • Physical and mental impairment: Drinking before driving can severely impair the driver's physical and mental reactions. 
  • Slow reaction time: Drinking relaxes the muscles and creates a delayed response in the brain, slowing down the drinker's reaction time. 
  • Poor coordination: A person affected by alcohol will begin slurring their words and unable to keep liquids or food inside their mouth. Their balance also becomes compromised.
  • Poor vision: A drinker's vision becomes increasingly blurry with each additional drink. Drinkers can experience ripple vision and the inability to focus. "Drunk Goggles" is a term referring to a drinker's depth perception issues after drinking.
  • Poor concentration: Drinking can severely impair the driver’s ability to understand traffic signs and signals, and stay in road lanes.
  • Poor depth perception: The drinker will experience a minimal field of vision. They will not be able to see how far or how close objects and people are in relation to the vehicle.

Risks of Driving Under the Influence

Risks of DUIs include:

  • Expensive: Going to court, as well as repairing damages to property or paying for injuries to involved parties, can be incredibly expensive, with or without insurance.
  • Car accidents: Impaired reactions lead to car accidents. While some accidents may fall under fender benders, others can prove to be fatal for the driver or other drivers on the road and pedestrians nearby.
  • Death: The intoxicated driver, the passengers, or even the driver and passengers of another car could be killed during an accident caused by driving under the influence.
  • Jail time: Drivers under the influences are arrested immediately in most states. 
  • Driving rights revoked: A judge can revoke a driver's right to operate a vehicle or even impound it. While not specific to alcohol use, vehicle impoundment ordinances are issued to prevent DWI/DUI offenders from repeating their crimes. People who violate impaired-driving laws typically lose their driver's licenses. 
  • DUIs can create public shame: DUIs can prevent a person from getting a job, or they could lose their job and be publicly shamed in their community.

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How to Spot an Impaired or Drunk Driver on the Road

If you witness impaired driving, safely pull over to the side of the road or a parking lot and call 911.

Reporting these types of behaviors on the road may just save the life of the driver involved as well as others:

  • Weaving and swerving
  • Driving on the wrong side of the road
  • Failure to yield
  • Using stop signs and red lights incorrectly

Drinking and driving is not something that a driver can risk. Not only can it cause personal harm or harm to others, but drinking and driving can be detrimental to the driver's future, landing them behind bars with the guilt and shame of harming another person.

However, there are treatment options that exist. There are both inpatient and outpatient programs for treating an addiction to alcohol as well as alcohol withdrawal syndrome, which comes from long-term alcohol use and dependency. 

There are also mutual support groups like Alcoholics Anonymous that can help those suffering from alcohol use disorder (AUD) and those who have multiple DUIs stay sober.

These groups feature communities of like-minded individuals with the same long-term goals: to stay sober and make amends with those they’d hurt and affected with their drinking.

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Types of DUIs

DUIs refer to citations issued by law enforcement to those drinking and driving over the legal limit. In most states, there are seven different types of DUIs.

  1. DUI per se: Per Se means as is. DUI per se is when a driver has a BAC of 0.08 or higher while operating a motor vehicle.
  1. DUI less safe: DUI laws are complex, and a person/drinker can be charged with a DUI Less Safe even if their BAC levels are under 0.08. This charge is when the driver may have ingested or inhaled other substances that, combined with alcohol, impair the driver even if the alcohol levels are below 0.08 BAC. A DUI less safe is charged if the driver refuses to take a BAC test.
  1. OWI/OUI/DWI: Some states like Iowa, Michigan, or Mane have a lesser offense than DUI Less Safe called an OWI/OUI/DWI. OWI/OUI stands for Operating While Impaired/Intoxicated, Operating Under the Influence, or Driving While Impaired. These are the different states' ways of defining the different types of DUI Less Safe. 
  1. DUI drugs: This is when a driver is operating a vehicle under some other substance besides alcohol. DUI Drugs charges could be brought against the driver if they have abused prescription drugs, used marijuana, or are high on methamphetamines. 
  1. DUI inhalants: This DUI refers to when a driver has intentionally inhaled and is under the influence of any aerosol, glue, or other possibly toxic vapor to the extent that it is not safe for the person to be operating a vehicle.
  1. DUI multiple substances: A DUI Multiple Substances is when a driver is under the influence of two or more substances or a combination of drugs, alcohol, and inhalants.
  1. DUI marijuana/controlled substance: This is a DUI given to a driver or person operating a vehicle under the influence of a controlled substance like Marijuana or opioid-based pain killers and psychotropics like Xanax.

Blood Alcohol Concentration (BAC) Levels & Driving Effects

.02 BAC 

.02 is the lowest level of measurable intoxication. A person may feel happy and relaxed, but they are likely to make poor decisions.

.04 BAC

At a .04 BAC, a person can lose control of small muscles, including focus. Judgment is also impaired. Inhibitions lower, and the ability to respond to situations, such as unexpected vehicles or objects on the road, becomes more difficult.

.08 BAC

Other than the state of Utah, .08 BAC is the legal driving limit in the U.S. It is illegal and unsafe to drive at this percentage.

A person at this level experiences a loss of coordination, impaired balance, and problems focusing. Inhibitions are also lowered, so risky behaviors are more common. 

0.10 BAC 

At .10 BAC, words become slurred. Thinking and reasoning skills are impaired. Thinking, walking, and talking are difficult. Vomiting can occur.

0.15 BAC 

A person is 380 times more likely to be in a fatal crash at .15 BAC than when sober. The drinker will be sloppy, have difficulty standing up, may become dizzy, and begin to vomit.

Many social drinkers will pass out at this level. Some will pass out behind the wheel.

0.20 BAC

Operating a vehicle while under this level of BAC is incredibly dangerous. At .20 BAC, a person's sense of reality is skewed.

People at this level may think they are driving a vehicle correctly. In reality, they are swerving, weaving, running red lights, and having trouble staying on the road. 

The person may also be “blackout drunk” at this BAC level. This is when the drinker does things they do not remember. 

0.25 - 0.30 BAC 

Severe intoxication occurs at this point. This person will likely experience:

  • Increased heart rate
  • Irregular breathing
  • Mental confusion
  • Dysphoria
  • Nausea
  • Vomiting.

Serious accidents, which include paralysis, brain damage, disfigurement, or even manslaughter, can result. 

0.35 - 0.40 BAC 

Between .35 and .40 BAC, the person will experience a loss of consciousness and may slip into a coma. 

0.40+ BAC 

.40 BAC results in coma. There is a high chance that death will occur due to respiratory failure.

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Physical Health Effects of Alcohol

Moderate alcohol consumption is generally safe, depending on your health and tolerance. However, frequent drinking can lead to various health effects.

Excessive alcohol use, or binge drinking, can affect your health in many ways, including:

Alcohol and the Liver

Consuming too much alcohol for an extended period contributes to three types of liver disease: steatosis (fatty liver), cirrhosis, and alcoholic hepatitis.

These diseases disrupt liver function, severely damaging the body over time. Women have a higher risk of developing alcohol-induced liver injuries than men.

Alcohol and the Heart

Directly after drinking alcohol, your heart rate and blood pressure rise. Once the substance is out of your system, your vital signs return to normal.

However, excessive alcohol consumption can:

  • Result in an irregular heartbeat and high blood pressure
  • Weaken heart muscle
  • Thin your blood
  • Increase the risk of a heart attack, an enlarged heart, heart failure, stroke, and death

Alcohol and the Pancreas

Drinking alcohol causes the pancreas to produce toxic substances. This can result in pancreatitis (inflammation and swelling of the pancreas).

Alcohol and the Digestive System

Alcohol directly aggravates your gastrointestinal tract (digestive system). This is because your digestive system is the first exposure site after alcohol ingestion.

Alcohol makes your stomach produce extra acid, leading to inflammation of the stomach lining (gastritis). Diarrhea, vomiting, heartburn, ulcers, and stomach pain after drinking are common side effects.

Alcohol and Cancer Risk

Regularly drinking alcohol, especially heavy drinking, increases your risk of developing certain cancers, including:

  • Oral cancer
  • Larynx cancer (voice box)
  • Esophageal cancer
  • Colon cancer
  • Liver cancer
  • Breast cancer (among women)

Alcohol and the Reproductive System

Women who regularly consume alcohol have a greater risk of infertility and decreased menstruation. Drinking during pregnancy can also lead to developmental issues in babies, including:

  • Fetal alcohol spectrum disorders (FASDs)
  • Miscarriage
  • Stillbirth
  • Physical, mental, or intellectual disabilities

Similarly, men who binge drink are more likely to develop erectile dysfunction than men who don't.

Alcohol and the Skeletal System

Alcohol can negatively affect the muscular and skeletal systems by thinning the bones over time. This increases the risk of falls, fractures, muscle weakness, cramping, and atrophy.

Alcohol and Immunity

Alcohol lowers your immune system. This makes it more difficult for your body to fight off infections, including the common cold and flu, as well as pneumonia and tuberculosis.

How Alcohol Affects Your Brain and Central Nervous System (CNS)

Heavy alcohol use negatively impacts reasoning, memory, and overall brain function. The hippocampus, which aids in learning and stores memories, can be particularly vulnerable to alcohol.

According to the University College London’s Whitehall II study recording 30 years of data from 1985 to 2015, even moderate drinking over extended periods can lead to brain shrinkage.10 Regularly drinking four or more alcoholic drinks daily increases your risk of hippocampal shrinkage by almost six times compared to non-drinkers.

This shrinking is because alcohol dehydrates tissues. Moreover, consistent dehydration can cause lasting damage to these sensitive areas.

Effects on Key Brain Regions and Associated Side Effects

Consistent alcohol consumption primarily affects the prefrontal cerebral cortex and cerebellum. The prefrontal cortex is critical in planning and decision-making. The cerebellum is responsible for balance and motor function.

When alcohol impairs these brain regions, it can result in various side effects like:

  • Memory problems
  • Poor coordination
  • Reduced cognitive performance
  • Vision issues
  • Difficulty concentrating
  • Low self-worth and confidence
  • Mood swings
  • Stress and anxiety
  • Blackouts

Determinants of Alcohol's Impact on the Brain

Multiple factors influence the severity of alcohol's adverse effects on the brain, including:

  • Frequency and quantity of alcohol consumption
  • Genetics, family history, and education level
  • Age and gender
  • Overall health status
  • The age at which you began drinking alcohol
  • Risks of prenatal alcohol exposure

The Biochemical Mechanism of Alcohol

The liver metabolizes alcohol. When you drink it, your stomach and small intestine absorb it into the bloodstream.

From there, enzymes in your liver break down about 95 percent of the alcohol you consume. Your body eliminates the remaining five percent through breath, sweat, or urine.

Alcohol's Impact on Neurotransmitters

While the liver breaks down alcohol, it also affects essential neurotransmitters in the brain. These chemicals include GABA, dopamine, and serotonin.

  • GABA: Alcohol increases the activity of GABA, a neurotransmitter that has a calming effect on the brain. This is one reason why alcohol can make you feel relaxed or sedated.
  • Dopamine: Alcohol consumption increases the release of dopamine, a neurotransmitter associated with pleasure and reward. This is why alcohol can initially make you feel happy or euphoric.
  • Serotonin: Alcohol inhibits the production and release of serotonin, a neurotransmitter involved in regulating mood, appetite, sleep, and pain sensation. This can lead to increased feelings of depression or anxiety.

The Role of Enzymes in Alcohol Metabolism

The primary enzyme involved in alcohol metabolism is the alcohol dehydrogenase (ADH). This enzyme converts alcohol into acetaldehyde, a toxic byproduct.

Another enzyme, aldehyde dehydrogenase (ALDH), converts acetaldehyde into acetate. This substance is less toxic. Your body also safely eliminates it from its system.

However, some people have genetic variations that affect the activity of these enzymes. These variations can determine how quickly or slowly you metabolize alcohol, making you more or less susceptible to its effects.

Mental Health Effects of Alcohol

Excessive alcohol use also leads to mental health conditions. A drinking-related condition is also known as a dual diagnosis or co-occurring disorder.

These include:

  • Depressive disorders: The most typical co-occurring psychiatric disease among people who misuse alcohol is major depressive disorder.13 Depression comes in many forms, including clinical depression, persistent depressive disorder, and bipolar disorders. The effects of alcohol come in waves throughout life or can be long-term.
  • Anxiety disorders: These conditions lead to constant worrying about daily situations. Alcohol-induced anxiety is separate from an independent anxiety disorder but is often hard to differentiate.
  • Other mood disorders: These include social phobia, post-traumatic stress disorder (PTSD), and panic disorder, which have an increased co-occurrence with alcohol dependence.
  • Increased risk of self-harm: This occurrence is high among alcoholics due to intoxication and lack of inhibition. Self-inflicted injuries, such as cutting or attempted suicide, are common among people with dual diagnoses.

Other Ways Alcohol Can Affect Your Life

Besides severely affecting your physical and mental health, alcohol can also lead to social and legal problems.

Learn more about how alcohol consumption can impact your life by reading the articles below:

Underage Drinking

Underage drinking can lead to several serious health issues. Teenagers’ brains are still developing, which makes them more susceptible to adverse physical and mental health effects.


Hangovers can make you feel horrible the day after drinking. However, for more frequent alcohol users, hangovers can seriously affect the quality of your life and lead to mental, physical, social, and interpersonal issues.

Physical Effects of Alcohol

Alcohol has dangerous effects on your physical health. Alcohol consumption increases your risk of injuries, liver disease, heart disease, gastrointestinal issues, cancer, and more.

Psychological Effects of Alcohol

Alcohol consumption also harms your mental health. Heavy alcohol use impairs brain functions, such as memory and reasoning. Scientists have linked frequent alcohol use to depression, anxiety, mood disorders, and self-harm (e.g., suicide attempts and cutting).

Insomnia and Alcohol Addiction

An estimated 20 percent of adults in the U.S. drink alcohol to help them fall asleep. However, alcohol use has a direct, adverse effect on a person’s sleep quality. Alcohol addiction can lead to several long-term sleep problems, including insomnia.

Drunk Driving and DUIs

Over 10,000 people die from drunk driving accidents every year.14 Drunk driving puts everyone on the road in danger. A Driving under the influence (DUI) offense may cause you to lose your license, pay a hefty fine, or end up in jail.

What is Alcohol Use Disorder (AUD)?

Alcohol use disorder (AUD), or alcohol addiction or alcoholism, is a chronic relapsing brain disease. It develops when you misuse alcohol despite knowing its adverse effects.

AUD affects the brain's operations. Therefore, it causes symptoms like compulsive behavior and intense cravings.

What are the Symptoms of AUD?

Common symptoms of alcohol use disorder include:

  • Inability to limit alcohol consumption
  • Failed attempts to reduce or stop alcohol consumption
  • Spending a significant amount of time drinking or recovering from drinking
  • Cravings for alcohol
  • Neglecting responsibilities and obligations
  • Continuing to drink alcohol despite physical, emotional, or social harm
  • Using alcohol in unsafe situations, such as when driving
  • Neglecting social activities and hobbies
  • Developing alcohol tolerance
  • Experiencing alcohol withdrawal symptoms when not drinking, such as sweating, tremors, and nausea

Treatment and Rehabilitation for Alcohol Dependency

Alcohol dependency is a chronic disease that requires professional treatment and ongoing support. Some common methods used to treat alcoholism include:


Detoxification, or detox for short, is removing alcohol from your system while managing withdrawal symptoms. This typically takes place in a medically supervised facility.

Inpatient Rehabilitation Programs

Inpatient rehabilitation programs provide intensive therapy and support for people struggling with alcohol addiction or substance abuse. You'll live in a specialized facility and receive 24/7 care.

This approach allows you to focus solely on your recovery without outside distractions. Moreover, you'll have access to therapy, support groups, and medical care during your stay.

Outpatient Rehabilitation Programs

Outpatient rehabilitation programs offer similar treatments as inpatient rehab. However, it allows you to continue living at home.

You'll regularly attend therapy sessions and support group meetings while managing your daily responsibilities. This option may be more suitable for those with mild AUD or those who can't leave their obligations for extended periods.

Support Groups

Support groups, such as Alcoholics Anonymous (AA), provide a community of people going through similar struggles. These groups offer emotional support, accountability, and guidance in maintaining sobriety.

Strategies for Responsible Drinking

You can lower your risk of developing an addiction to alcohol by practicing responsible drinking. Here are a few strategies you can use to drink responsibly:

  1. Set limits and stick to them.
  2. Alternate alcoholic drinks with non-alcoholic beverages.
  3. Eat before and while drinking.
  4. Pace yourself and sip your drink slowly.
  5. Avoid binge or excessive drinking by consuming less than four drinks for women and five for men daily.
  6. Avoid drinking when you are feeling stressed or sad.
  7. Avoid drinking to cope with problems, emotions, or stressors.
  8. Monitor your alcohol consumption and cut back if necessary.
  9. Seek help if you can't control your drinking habits.

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Updated on February 15, 2024
6 sources cited
Updated on February 15, 2024
  1. Esteban-Muir, R. P. (2012, September). "Community-Based Impaired-Driving Programs: Local  Ordinances and Other Strategies Addressing Impaired Driving. (Report No. DOT HS 811 678)". Washington, DC: National Highway Traffic Safety Administration.

  2. Anonymous. “Drunk Driving.” NHTSA, National Highway Traffic Safety Administration, 17 Jan. 2020.

  3. Car Crashes Are the #1 Cause of Preventable Death for Teens.” National Safety Council.

  4. Monico, Nicolle. “Blood Alcohol Level: BAC Chart Content Meanings.” Alcohol.org, 1 May 2020.

  5. Driving Laws Published by NOLO. “Blood Alcohol Level Chart: Are You Too Drunk to Legally Drive?” https://dui.drivinglaws.org/.

  6. National Institute on Alcohol Abuse and Alcoholism. “Treatment for Alcohol Problems: Finding and Getting Help.https://www.niaaa.nih.gov/.

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