Drinking and driving aren’t a good mix.
We don’t recommend anyone get behind a wheel after having drinks. But, there are a few situations where you can do so without posing a risk to yourself and others.
The question is, how much beer can you drink before driving?
Or in general, how much alcohol can you consume and still be fit to drive?
In this article, we look into alcohol metabolism to see its effects on mental cognition. We also want to know:
- How much can it affect our mental abilities.
- How long it takes for alcohol to start influencing our motor skills.
- The number of drinks you can consume before getting drunk.
Lastly, we ask how long does it take for alcohol to get out of our system. This includes it being in our blood, breath and urine.
How Much Alcohol Do We Consume?
According to the National Institute on Alcohol Abuse and Alcoholism (NIAAA), over 86% of individuals 18 years or older have drank alcohol at least one in their life.
Of this number, around 25% of those aged 18 and above have engaged in binge drinking in the last 30 days. We’ll look more into binge drinking later in the article.
Alcohol, when enjoyed moderately has been shown to offer us a number of health benefits. In excess, it does more harm than good.
The Centers for Disease Control and Prevention (CDC), estimates that drinking too much alcohol is responsible for nearly 88,000 deaths each year. Around 70% of that being men.
This figure involves automobile accidents caused by drinking and driving, falls, accidents, fires, as well as suicides and homicides.
Of that total, around 30% or 10,000 deaths, were from driving while being impaired by alcohol.
To put things into perspective, nearly 30 people die in the U.S. from alcohol-related motor vehicle accidents. This is around 1 death every 51 minutes.
In addition, the cost of alcohol-related crashes in the U.S. amounts to more than $44 billion a year.
So as good a feeling as alcohol gives us, too much can be dangerous.
The Law on Drinking and Driving
According to the National Minimum Drinking Age Act that passed by Congress in 1984, the minimum legal drinking age in the U.S. is 21 years old.
Also, if you’ve had a number of drinks and get behind the wheel of a vehicle, you could be charged by the law for a crime.
In most states, drug and alcohol related violations are based on BAC (Blood Alcohol Content).
Some people also refer to BAC as Blood Alcohol Concentration. We’ll discuss more about BAC later.
With drinking and driving, one thing’s for sure.
You are in violation of the law if you’re operating a motor vehicle and fit the following criteria.
|Criteria||Blood Alcohol Content|
|Under 21 years old||0.02% or higher|
|21 years & older||0.08% or higher|
|Operating a Commercial Vehicle||0.04% or higher|
Note that some states there are lesser charges as well.
In Colorado for example, drivers found to have BAC levels over 0.05% but under 0.08% are charged with DWAI (Driving While Ability Impaired).
Because anyone under the age of 21 years old isn’t legally allowed to drink, states have what’s called the Zero Tolerance Law. This makes it illegal for anyone under the legal drinking age to get behind the wheel with a BAC of 0.02% or higher.
There’s one final note to remember.
If you are pulled over under suspicion of driving under the influence or being impaired, even if you pass the field sobriety test and breathalyzer test (BAC below 0.08%), you may still be found guilty.
The arresting officer may charge you if they believe you are noticeably impaired and not fit to drive. This gives them probable cause based on behavior.
DUI and DWI: What They Mean
To learn more about the specific details on each state’s fines and penalties for DUI and DWI, check out the DMV’s page here.
Blood Alcohol Content
In the section above, we touched a bit on Blood Alcohol Content (BAC).
Blood Alcohol Content, or Blood Alcohol Concentration, is the amount of alcohol in a person’s body. This number, which is expressed in percentage (%), measures the weight of alcohol for a specific amount of blood.
A BAC level of 0.08% for example, tells us that 8% of a person’s blood is alcohol.
Because alcohol quickly gets into our system after drinking, it can affect our brain’s cognitive function and reaction time fairly fast. In as little as 15 minutes after consuming a drink, alcohol can already be detected in our blood.
These effects make it necessary to keep the level of alcohol in blood down. This applies to any kind, including beer, wine, whiskey or other drinks.
Below is a chart of the different BAC levels that are often used as guidelines for law enforcement officers.
It gives you an idea why state laws specifically use certain limits like 0.08% for DUI/DWI and 0.04% for operating commercial vehicles.
The Blood Alcohol Concentration (BAC) chart below also lists the typical effects on people and driving under the influence.
This chart has been adapted from the CDC’s Motor Vehicle Safety Section.
How Our Bodies Metabolize Alcohol
Knowing about alcohol metabolism gives you a better understanding of why it isn’t safe to drive. This is true even when you just had a few drinks.
Here’s a quick summary of what happens after alcohol enters our mouth.
When we drink a drop of beer, wine or any alcoholic beverage it takes just a few minutes before the alcohol is detected in our blood.
The more drinks you have, the higher the concentration in your blood.
When your blood alcohol concentration reaches 0.08%, you’re considered legally intoxicated.
And the only way your BAC can go down, and eventually get back to 0.00%, is after the liver break downs and metabolizes the alcohol.
Alcohol is quickly absorbed by the body.
Why does alcohol reach our blood so fast?
It is because absorption starts in the stomach.
Normally, the stomach’s job is to break down food with stomach acid. This makes it easy for the small intestine to absorb the vitamins, minerals and other nutrients.
With alcohol, our bodies quickly recognize that it is toxic.
So, our bodies want to get rid of alcohol quickly as it can.
Instead of treating it like food which slowly goes through digestion and absorption to get the most out of the nutrients, the body tries to expel the alcohol out of it as quickly as possible.
Another problem is the body also doesn’t have anywhere to store alcohol.
So keeping it in for long periods of time only damages our tissues and cells. This gets worse as the alcohol content builds up.
Alcohol gets it into our bloodstream.
Instead of slowly going through the stomach then small intestine, alcohol seeps through the lining of the stomach. This allows it to get into our bloodstream quickly.
How long does alcohol take to kick in?
Because of what happens in our digestive system, it takes only a few minutes to detect BAC in our blood.
Once alcohol gets into the bloodstream, it can quickly reach our brain.
This lets it impair our judgment and affect our motor skills.
So even with the first drink, there’s already an effect in our cognitive ability.
The more alcohol you drink, the more impaired you get. Also, the higher your blood alcohol concentration goes.
Finally, alcohol is metabolized in the liver.
After some time, the alcohol in the blood makes its way to the liver. This is what eventually will metabolize it. And, allow our bodies to get rid of it.
The liver takes a 2 step process in converting the toxic nature of the alcohol into components that the body can get rid of.
When the liver is done, alcohol is broken down into CO2 (carbon dioxide) and water. We breathe out the CO2, while the water exits the body via urine. The latter is why you find yourself going to the bathroom hours later.
Only when the liver is completely done metabolizing the alcohol does your BAC level return to 0.00%.
The video below puts the entire process down in simple terms. It shows what what happens in the body when you consume alcohol. It also shows you how fast the body can get rid of alcohol.
Factors that Affect Blood Alcohol Concentration (BAC)
When you have drinks with friends, you’ll quickly learn that some people “can’t hold their liquor”. This means they can drink a lot before getting drunk.
Also,you’ve probably noticed that drinking on an empty stomach gets you drunk faster than when you drink after eating food.
How much alcohol affects a person depends on a lot of factors. Combined, they are the reason why some people get tipsy really fast, while others take a while.
These factors include:
What and How Much Did You Drink?
- The type of drink you’re having. Some drinks contain more alcohol than others. Wine, for example, averages around 15% alcohol. Beer only has around 5%. This means drinking the same amount of beer and wine will make the wine drinker consume more alcohol.
- The number of drinks you consume. The more drinks, the higher your BAC. You can consult the charts below to estimate your BAC after a few drinks.
- How much you drink per hour. One of the proven ways to ensure your BAC stays at legal limits is to consume 1 drink per hour. We explain below the definition of 1 drink. In general, the more drinks per hour, the higher your BAC. An average male will go over the legal driving BAC limit at 3 drinks an hour.
- Age. The older we get the longer our body takes to metabolize what we drink or eat. This includes alcohol.
- Gender. Bigger men don’t get drunk as fast. Their larger stature means their bodies have more water to dilute the alcohol. Women’s bodies meanwhile, are designed to have more fat. Alcohol isn’t able to get into fat cells. So, it becomes more concentrates in the blood. That means, if a male and a female who weigh the same drink the same amount of alcohol, the women will feel its effects faster. She will also have a higher blood alcohol content in her system.
- How much you weigh. The more you weigh, the bigger the area and amount of water to dilute the alcohol.
What’s in your belly?
- How much food you ate before drinking. Food slows down alcohol absorption. So drinking on an empty stomach results in being more affected by the beer or wine. Having food in your stomach keeps alcohol from being absorbed. This results in a lower BAC.
- How hydrated are you. The less hydrated you are, the less water there is in the body to dilute the alcohol.
- What medications you’re on. Certain medications increase the effects of alcohol.
All these factors influence how much your blood alcohol content is after each drink.
What is “One Drink”?
The National Institute of Alcohol Abuse and Alcoholism defines “one standard drink” to be 14 grams or 0.6 oz. of pure alcohol.
Below is an illustration of what that amount is based on the different popular drinks. The image also shows how many ounces there are in one standard drink of beer, wine, and other liquor.
This means that 1 drink can equate to:
- One 12 oz. can of beer which has 5% alcohol.
- A 5 ounce glass of table wine which has 12% alcohol.
- Or, 1.5 ounces of brandy or cognac which have around 40% alcohol.
The higher the alcohol concentration of the drink, the fewer needed to reach one drink.
This also explains why no one type of alcohol is “safer” than the other. Beer is no better than wine. And wine is no better than whiskey, rum or gin.
What’s important is the number of drinks (equivalent to 14 grams of pure alcohol) and not the type of alcohol.
Blood Alcohol Content (BAC) Charts Guideline
The reason we went through the trouble of defining what one drink was above, is that we’re now going to use that definition to estimate your BAC (blood alcohol content).
The basis of your BAC will be your weight and number of drinks you’ve had.
The charts below will tell you how many drinks you can have before driving. It does this by estimating your BAC level based from the number drinks and your body weight.
The charts below are classified into those for men and those for women.
The reason is, as we’ve mentioned above, men and women absorb and metabolize alcohol differently. This is due to the difference in body makeup and structure.
Interpreting the BAC Charts
Each of the charts represents the estimated BAC. They show:
- The number of drinks on the left most column.
- Your body weight in pounds on the uppermost row.
To check your estimated BAC level, look at where your weight and number of drinks cross.
For both men and women, we’ve included BAC charts for 1 to 5 hours after consuming alcohol.
- This gives you an idea of what your BAC level will be a few hours from now.
- It also shows you how fast the body and the liver metabolize the alcohol.
Each of the charts is color coded.
We did this to make it easy to see what your drinking limits are based on how much you weigh.
The different colors give you an indication of which levels make it legally too drunk to drive. They also tell you when you’re already impaired.
Our color guidelines are as follows:
- GREEN: represents BAC levels of 0.02% to 0.04% This means take caution. You’re almost getting impaired.
- YELLOW: represents BAC levels of 0.05% to 0.07%. Your senses are impaired.
- RED: represents BAC levels of 0.08% & over. You’re legally drunk.
The colors also make it easy to see on an hour by hour basis, how much alcohol is being metabolized by the liver.
Approximate Blood Alcohol Content (BAC) Charts for Men
Here is the blood alcohol content charts for men based on how much you weigh and how many drinks you’ve had.
Each chart tells you your BAC based on the number of hours since you’ve stopped drinking.
Here’s an example of how to use the chart.
Assuming you’re a man weighing 180 pounds, and have had 5 drinks.
- Chart 1 tells you that after an hour, your BAC is 0.09%. This means you shouldn’t drive.
- Chart 3 tells you that after 3 hours, your BAC is 0.05%. You’re not drunk. But, your senses are still impaired.
- Chart 5 tells you that after 5 hours, yourBAC is 0.02%. You’re almost back to 0% BAC.
Approximate Blood Alcohol Content (BAC) Charts for Women
Here’s the same set of charts. This time they show how much alcohol is still in a woman’s system based on how many drinks they’ve had and how much they weigh.
For a guide, please refer to the example we did in the BAC chart for men.
Note: Blood alcohol concentration charts adapted from How to Control Your Drinking (Miller and Munoz)
Note that the charts above provide an estimate and offer a general guideline.
They do not take into account all the factors that affect your BAC level.
The only way to make sure that your blood alcohol level stays within the legal limits is to have 1 drink per hour.
How Long Does Alcohol Stay in Your System
The charts above give you a good idea of how long it takes for the body to get rid of alcohol. The colors and BAC% offer a clue on how long it takes for alcohol to get out of your system.
That said, the charts, as their labels indicate, estimate how much alcohol is still in your blood.
Law enforcement officials have different ways of detecting alcohol in our bodies. And, they use a variety of tests to do so.
As a quick summary of the different tests. And, how long before alcohol isn’t detected by each test. We’ve covered blood alcohol content above. So, here are the others.
- How long does alcohol stay in your breath for a breathalyzer test? Within a 24 hour period, breathalyzers will be able to detect alcohol in your system. But, if a saliva test (ethyl glucuronide test) is done, it will be able to detect traces up to 12 days from the last time you drank.
- How long does it take for alcohol to get out of your urine? Urine tests, or EtG Urine Alcohol Tests, can detect alcohol in your system for a longer period. It typically will find traces up to 3 or 4 days. This is around 80 hours from the last time you consumed a drink. This also why the test is sometimes referred to as an “80 hour test”.
Other special notes and circumstances:
- As early as 20 to 25 minutes from consuming alcohol, your body will start to excrete it through your urine. This is where how much your drink and the other factors come in. They determine how much more alcohol the liver needs to metabolize. But once that process is done, your body would have gotten rid of the beer, wine or other liquor you consumed.
- A healthy liver generally metabolizes 1 ounce of alcohol per hour. After this, it will depend on how much you drank and what type of alcoholic beverage it was. If you only drank an ounce of alcohol, then soon after an hour alcohol is out of your system.
A special circumstance would be vomiting.
If you do happen to vomit within a few minutes of drinking, then there’s a chance the alcohol wasn’t able to get into your bloodstream.
But, if you wait 20 or 25 minutes after drinking before vomiting, this does little to nothing in cutting down the amount of alcohol that’s in your bloodstream. By then, it would have already been absorbed into your system.
Safety Precautions You Can Take
The only way to be completely safe is to not drink and drive.
If you do decide to have a few drinks, here are a few tips that can ensure everyone’s safety.
- Take a taxi. Anytime you plan on drinking or have had a few drinks, call for a cab instead of driving. Keep a lookout for your friends as well. For friends who’ve had a bit to drink, take away their keys. Then, put them a taxi instead of letting them drive home.
- Have a designated driver. Before any event or drinking outing with friends, designate one person to be the driver who won’t be drinking. This way, the driver will get everyone home safe.
- Plan ahead. If you’re hosting and will be serving alcohol, inform your guests to allow them to plan ahead of time.
- Stay over at a friend’s home. If you’ve had too much to drink, ask to stay over at a friend’s place instead of driving home. The same is true if a friend is drunk. Offer to have them stay over to keep them from driving home.