Driving Under The Influence of Alcohol
Driving Under The Influence of Alcohol

Driving Under the Influence of Alcohol: Drinking and Driving Laws

Updated Nov. 16, 2019

Drinking and driving is a serious crime. It is also one of the most stupid and dangerous things a person could choose to do. Driving safely requires sharp motor skills, plus the ability to think clearly, act calmly and exercise good judgment. Even when a driver does everything “right” they are still at risk of being involved in a crash or collision, as our nation’s roadways are inherently dangerous. If you get behind the wheel while intoxicated, the risk of injury or death you face under normal circumstances becomes a likelihood. Alcohol’s effect on your body and mind will render you physically incapable of driving safely – even in relatively small quantities. A person who chooses to drive while under the influence or alcohol would be extremely lucky to make it to their destination in one piece.

Driving under the influence (DUI) is illegal and incurs harsh punishments. Unfortunately, the law itself is not enough of a deterrent to prevent people from driving while drunk. Each year, alcohol-impaired crashes account for around 30% of all traffic crashes across the United States. In 2016, a total of 10,497 people died in completely preventable alcohol-fueled collisions.

As a new driver, you must understand the threat alcohol poses to your safety and the safety of your fellow road users. Even if you are over 21 and can legally drive with a small amount of alcohol in your system, you would be foolish to do so. You might not be breaking the law, but you will still be endangering yourself, as no amount of alcohol is safe.

Most people have at least a vague understanding of the ways in which drinking alcohol can impair their driving ability in the short-term. Though they think that drinking is safe, providing they sober-up before driving. This ill-considered school of thought completely disregards the long-term risks of regular alcohol consumption. As you will see later in this module, regular drinking leads to a gradual decline in mental, physical and emotional health. If you become a habitual drinker, the driver you are five years from now will be considerably less competent and safe than the driver you are today.

Who is most at risk of DUI?

Alcohol intoxication will render any driver unsafe, whether they have been driving for two months or twenty years. However, teenagers and young people are more at-risk of choosing to drive while impaired by alcohol and thus more likely to be injured or killed in an alcohol-related collision. Teenagers suffer from the unfortunate double-whammy of being less tolerant to the effects of alcohol AND more likely to binge-drink. It is no wonder that car crashes are the leading cause of death for teenagers around the country and that very often, alcohol intoxication is the primary cause of these deadly collisions.

Research conducted over the past decade has shown that:

  • Drivers aged between 16 and 20 are ten times more likely to be involved in a fatal collision than drivers over 21 years old.
  • Drivers under the age of 21 account for 17% of all fatal alcohol-related collisions, despite only representing 10% of licensed drivers across the entire United States.
  • In 2011, nearly one million high school teenagers admitted to driving under the influence of alcohol.
  • Drivers aged between 21 and 24 are the second most at-risk of being involved in a fatal traffic collision.
  • In 2012, 32% of drivers aged 21 to 24 who were involved in fatal collisions had a BAC of 0.08% or above (over the legal limit).
  • The number of young drivers involved in fatal crashes each year rose by 3.6% between 2015 and 2016. More than one third of these crashes involved alcohol.

Drinking and driving laws

While the penalties for drinking and driving vary quite a bit from state to state, the rules concerning DUI are practically identical from coast to coast. Drivers over 21 years old may not operate any motor vehicle with a blood alcohol concentration (BAC) of 0.08% or higher. In most states, the legal definition of “motor vehicle” includes cars, trucks, bicycles, motorcycles, snowmobiles, jet skis and golf carts. In some areas, horse-drawn vehicles are also included in this law.

Practically every state in America imposes some form of “zero tolerance” policy on drivers under the age of 21. This means that underage drivers may not operate a motor vehicle with a blood alcohol concentration of 0.01% or over. Breaking this law can carry extremely strict penalties and is likely to result in a license suspension.

Most states also impose lower BAC limits on commercial truck and passenger vehicle drivers. Typically, this limit is around 0.04%. Accurate and up-to-date information on the DUI laws in your state can be found in your driver’s handbook.

Understanding the risks

This essential module is all about understanding the risks of drinking alcohol. It is not enough simply to know that “drinking and driving is a bad idea”, as every qualified driver knows that and yet millions of people still drive their cars while intoxicated every year. Alcohol is a deadly drug that manipulates your mind, personality and judgment to the degree that you may choose to drink and drive, even if you think you would never cross that line.

The adverse effects of alcohol intoxication start to kick in the very moment you begin your first drink. Remaining within the legal blood alcohol concentration limit is not enough to keep you safe.

Blood alcohol concentration (BAC)

To begin our DUI module, we will discuss blood alcohol concentration (BAC), what it means and how it relates to the amount you have had to drink. Most drivers know that the legal BAC limit is 0.08% and can reel that information off at the drop of a hat. However, ask them what that translates to in terms of number of drinks, or ounces of alcohol consumed, and you are likely to get a variety of wildly misinformed responses.

If you have consumed any alcohol, your resulting blood alcohol concentration will be a product of various factors. These include:

  • The type of alcohol you drank
  • How quickly you drank it
  • Whether anything else is in your system which would influence the rate at which you absorb alcohol (carbonated drinks, food, other drugs)
  • Your age, gender, weight, alcohol tolerance and genetic make-up

Figuring out whether you can legally drive after drinking is not a precise science. It is no wonder that so many drivers get it wrong! However, there are calculations which can help you form a rough estimate of your BAC based on when you drank, how much you consumed, your weight and your gender. The formula for this (and a straightforward explanation to accompany it) can be found in our full BAC module.

Just as the number of drinks you consume does not perfectly correlate with your resulting BAC, your BAC does not absolutely determine how “intoxicated” you are. People respond to different blood alcohol concentrations in different ways. One person may be hopelessly impaired at 0.02%, while another is relatively alert and capable at 0.06%. This problem is the reason why police officers have the power to arrest motorists for driving under the influence, even when their BAC is less than 0.08%. If you have any alcohol in your system and you are showing signs of intoxication, you can expect to spend the night in a jail cell.

Alcohol intake and elimination

In part two of this section, you will learn what happens in your body when you consume alcohol. This will include:

  • How alcohol is absorbed into the blood
  • How alcohol is expelled from the body

A person begins to experience the effects of alcohol intoxication as soon as alcohol passes through the brain via the blood stream. This happens sooner than you may think, as some alcohol is absorbed directly into the blood via the mouth and upper digestive tract. Most people eliminate alcohol from their system at a rate of around 0.015% per hour, though this varies a touch depending on metabolic rate. This means that an average person with a BAC of 0.08% will take around 5.3 hours to completely sober-up, from the point at which they stop drinking.

Alcohol consumption and sensory impairment

Alcohol travels around your body via the circulatory system and is passed through your brain. The human brain operates via a complex system of chemical and electrical signals, through which it controls every conscious and unconscious action you make. As alcohol is a chemical itself, it interferes with the delicate balance of chemicals in the brain. This causes mood changes, a decline in cognitive ability (the ability to think clearly and exercise judgment), vision and impaired motor skills. The more alcohol passes through your brain, the more extreme these effects will be. Continuous alcohol consumption will eventually result in lethal poisoning, whereby the brain’s control over your breathing and heart rhythm are disrupted. Impairment of the senses is one of the earliest intoxication effects to kick-in.

Even mild alcohol intoxication can result in a deadly car crash, as your chances of making a fatal error will increase as your mental and physical skills decline. If your senses are impaired:

It is important to understand that ANY sensory impairment increases risk. You may not realize you are impaired but from the first sip of your first drink, you will be more likely to miss vital information on the roadway and be involved in a fatal collision.

Alcohol consumption and physical impairment

As soon as alcohol has entered your blood stream, no part of your body is safe. It is important to remember that alcohol is a poison. Some organs, tissues and bodily functions will be affected more than others, but your entire body will be impaired to some extent.

Alcohol disrupts heart rate, blood pressure, liver function, breathing, the digestive system, kidney function and your nervous system’s ability to control and coordinate your body. Later, we will explore the long-term health implications of these physical impairments in more detail. Next up, let’s look at how physical alcohol impairment will affect your behavior behind the wheel.

The physiology of intoxicated driving

Your ability to drive safely will be impaired by alcohol intoxication, even if you feel alert and able to think clearly. The fact of the matter is that your cognitive skills probably are impaired by alcohol, you may just be unaware of it. Even if you have complete control over your mind, your alcohol impaired body will let you down. Physical impairment sets in alarmingly quickly when you start drinking! Research has shown that BACs as low as 0.02% can significantly impair driving ability. This module contains a useful break-down of how most people respond to alcohol at different BAC levels. Needless to say, no amount of alcohol in your blood is entirely safe.

The physical effects of alcohol consumption will render you less able to search the roadway for hazards and upcoming changes, as your depth perception, focus, peripheral vision and ability to adapt to light changes will be impaired. You will overlook important details, misjudge distances and confuse objects. Without accurate visual information, you cannot hope to make safe driving decisions. Even if you can see perfectly well (doubtful) and settle on appropriate responses to the changing roadway environment (unlikely), there is a strong chance you will not be able to follow through with those responses properly. With loss of coordination, balance and muscle control, you will make mistakes during even the most basic of driving maneuvers.

Cognitive and emotional impairment

Alcohol affects your mood, emotional state and cognitive skills. In order to make safe decisions behind the wheel, drivers must maintain a calm and positive emotional state. Feelings of anger, sadness or anxiety will result in risky or inattentive driving behavior. As alcohol interferes with the brain chemicals that regulate mood and personality, people who are intoxicated often experience sudden mood swings and extreme emotions.

As alcohol is a depressant which effectively slows down brain function, it will impair your memory and reasoning skills. This may result in irrational behavior and illogical actions while driving. As you will already be working with insufficient information due to your impaired senses, you are likely to drive in a way that is inappropriate and unsafe based on current roadway conditions. Lack of reasoning ability is enough to seriously endanger you, even if your vision were not affected by alcohol. For instance, you may see that there is ice on the roadway but fail to reduce your speed, as your brain may not be able to access relevant memories from your driver’s training to recognize the danger.

If your poor vision and lack of reasoning ability do not put you in considerable danger, your impaired judgment surely will. People who are under the influence of alcohol exercise notoriously bad judgment, often failing to recognize and respond to extremely hazardous situations. Going back to the above example: you may see the ice on the road and recognize that you should adjust your speed yet decide not to slow down anyway! Keep in mind that teenagers and young people are particularly susceptible to making alcohol-fueled bad judgment calls while driving. Learn more about how alcohol consumption will distort your emotions and impair your mind, in this essential article.

Alcohol and your driving skills

While driving, you are required by law to do everything possible to increase safety and reduce danger. By remaining attentive to the roadway, maintaining their vehicles, operating within the boundaries of the law and utilizing a space management system, drivers can preemptively avoid conflicts, collisions and accidents. Where driving is concerned, your job is to always take the safest possible action. It is impossible to do this with alcohol in your system. In fact, the moment you get into the car while intoxicated, you have already failed.

There is a great deal of reliable evidence proving alcohol’s impact on your vision, focus, memory, reasoning skills, judgment and motor skills. One study discussed in this section was able to record the outcome of these impairments on a group of intoxicated drivers. It demonstrated that intoxicated drivers:

  • Misjudge speed
  • Have poorer braking skills
  • Struggle to maintain their lane position and manage space
  • Are considerably less capable of correcting mistakes

You would not go for a drive in a vehicle that has an engine or brake malfunction – that would be asking for trouble! The same is true of drinking and driving. When your body and brain are malfunctioning, they cannot safely operate a motor vehicle.

Alcohol and emotional fitness

Being emotionally “fit to drive” is an incredibly important and often overlooked issue, which we have touched upon briefly in previous modules of this course. Here, we take the time to explore the topic in greater detail. The emotions you experience while driving matter, because they influence your behavior and decision-making skills. A calm and tranquil driver is unlikely to respond dangerously if another vehicle cuts in front of them in a line of traffic. Whereas an angry, frustrated driver may respond to the same situation by sounding their horn, shouting, tailgating or even ramming the offending vehicle from behind.

Powerful emotions – even positive emotions – can be dangerous. Due to alcohol’s chemically disruptive affect on the brain, drinking creates a Russian Roulette-like situation whereby you cannot predict which emotion you end up with, and, there is a strong potential for disaster.

Alcohol can:

  • Lead to “out of character” behavior
  • Dramatically change a person’s emotional state
  • Intensify pre-existing emotions
  • Render a person incapable of bringing their emotions back under control

Strong emotions which are fueled by alcohol are especially dangerous, as they are usually accompanied by other intoxication effects such as poor judgment and reduced inhibitions. A driver suffering with these effects in addition to a powerful negative emotion is a ticking time-bomb. They will overreact to the slightest adverse event on the road, feel justified in taking extreme action and they will not care who witnesses them doing it.

The emotions you experience while under the influence of alcohol will be affected by stress, your mental health, your tolerance to alcohol and various other factors. You may also have different emotional responses even when conditions are the same – it is impossible to predict. Find out more about these variables and the likely effect of alcohol on your emotions in this module.

Alcohol poisoning

Alcohol is a dangerous and destructive drug, even if you drink it in “ideal” conditions and are in no way tempted to drive. As drinking alcohol impairs judgment, people very often continue drinking until they pass out or are too ill to continue. As BAC rises, alcohol’s impairment of the nervous system and brain will reach a dangerous level. Eventually, your heart and lungs may be affected to the degree that you stop breathing or suffer heart failure.

Even before this reaching this level of intoxication, death by alcohol poisoning is a real risk at high BACs. Vomiting is a common symptom of excessive alcohol consumption. If your body is compelled to vomit while you are asleep or in a drunken stupor, your gag reflex may be impaired to the degree that you inhale vomit into your lungs and drown.

Knowing what to do if you suspect one of your friends or family members is suffering with alcohol poisoning can mean the difference between life and death. You can find that information here. If you are in any doubt, call 911.

The long-term health impact of alcohol

Most driver’s education programs deal exclusively with the short-term dangers of alcohol consumption, focusing on intoxication and how it will render you an unsafe driver. These issues are essential, though we believe it is also important to consider the long-term effects of regular drinking. As a teenage driver, it is difficult to avoid exposure to alcohol. Your friends may be experimenting with alcohol and you yourself may have been in situations where you are tempted to drink. To make the right decisions under such circumstances, you must fully comprehend the consequences of your actions. Alcohol is dangerous, but it is also physically and mentally addictive. For too many people, one seemingly harmless drink turns into several drinks, binge drinking, and life-long alcohol dependency.

This sobering module outlines the true physical impact of regular alcohol consumption. Every essential system and organ in your body is vulnerable to the effects of alcohol and will begin to fail, if you drink too regularly for too long. If you become physically addicted, you will not be able to stop drinking and may not even want to, despite seeing the damage it is doing to your health.

Long-term alcohol consumption threatens the well-being of your entire body, though it is particularly harmful to the liver. As your liver must work tirelessly to remove alcohol from your blood every time you drink, regular alcohol consumption will wear out and kill off your liver’s cells and tissues. This can lead to a deadly but tragically common condition, called alcoholic liver disease. Refusing to drink and drive will dramatically lessen your chances of dying in an alcohol-fueled traffic collision. Though, if you choose to drink regularly, you may still end up dying prematurely due to alcohol-related illness.

A destructive addiction

Alcohol ruins lives in more ways than one. You might consider a heavy drinker who manages not to die in a drink-driving incident or as a result of alcohol-related illness to be fortunate. The truth of the matter is probably quite the opposite. Abusing alcohol will eventually change your personality until you bear little resemblance to the person you once were. Your priorities will shift, and you will become distanced from loved ones, until all that is left in your life is the compulsion to drink alcohol. Alcohol addiction is so all-consuming that it frequently leads people to hurt and endanger those closest to them. If you are irresponsible with alcohol, you could one day become that person.

Some people are more at-risk of becoming addicted to alcohol than others. If your parents or close family members have a troubled relationship with alcohol, there is a strong chance that you will too. This final module addresses the wider life-impact of alcohol addiction and the factors which contribute to it. Understanding when you are at-risk can install caution and help you to maintain a healthy relationship with alcohol. Though, the safest decision will always be not to drink at all.

Drinking is a slippery slope

If you are ever in a situation where you think you can have “just one drink”, consider this: having one drink may impair your judgment enough that you decide to keep drinking. If you become extremely intoxicated, there is a strong chance that you will behave in a way that causes you shame, guilt or some other emotional upset when the alcohol wears off. You will then be extremely susceptible to getting stuck in a vicious circle, whereby you drink again to relieve emotional pain, only to end up sadder, angrier or more guilty than you were before – so you keep drinking. Always remember that this is how alcohol dependency begins: with just one drink.

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