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Blood Alcohol Concentration and What it Means for DWI Charges

Alcohol consumption is a frequent social activity for many adults. While having a drink or two is usually not a cause for concern, it's important to be aware of the potential risks of excessive alcohol consumption, such as driving under the influence. It's always a good idea to drink responsibly and make alternative arrangements for transportation if you plan to drink.

What is BAC (Blood Alcohol Concentration)?

Blood alcohol concentration (BAC) is a measure of the amount of alcohol in a person's bloodstream. It is expressed as a percentage of the total blood volume. BAC is typically measured in grams of alcohol per 100 milliliters (about 3.38 oz) of blood (g/100mL) or as a percentage.

It's important to note that BAC is not the same as the feeling of being drunk. Some people may feel impaired even if their BAC is below the legal limit, while others may not feel impaired even if their BAC is above the legal limit. BAC is a scientific measure of the amount of alcohol in the bloodstream and should be taken seriously. Generally, a breath sample is taken to determine a person’s BAC when an officer suspects that the driver has been driving while impaired. But even if the blood alcohol concentration is not obtained until a later time, a pseudo-scientific process called retrograde extrapolation can be used to estimate what the person’s BAC was while driving.

How Many Drinks Until I Reach .08 in North Carolina?

In North Carolina, it is illegal to drive with a blood alcohol concentration (BAC) of .08 or higher. You might not know that a driver under the limit of .08 can also be charged with a DWI if the person is proven to be impaired. The number of drinks it takes to reach .08 (or an impaired state) can vary from person to person depending on several factors, including those listed below.

Factors that Affect BAC Levels:

The Amount of Alcohol in Each Drink

The amount of alcohol in each drink is a crucial factor in determining how many drinks it takes to reach .08 BAC. In North Carolina, a standard drink is defined as 12 ounces of beer, 5 ounces of wine, or 1.5 ounces of distilled spirits. However, some beers and wines can have a higher alcohol content and mixed drinks can contain more than one standard drink. For example, a typical 12-ounce beer has an alcohol content of around 5% alcohol by volume (ABV), while a 12-ounce craft beer can have an ABV of 8% or higher. Similarly, a glass of wine can have an ABV of anywhere from 5% to 14%, depending on the type and serving size. A mixed drink like a Long Island Iced Tea can contain up to three or four standard drinks.

The Size of the Person Who Is Drinking

The size of the person who is drinking also plays a role in how many drinks it takes to reach .08 BAC. Generally, larger people can metabolize alcohol more quickly than smaller people because they have a larger liver and more body water to dilute the alcohol. However, body composition, gender and genetics can also play a role in how quickly alcohol is metabolized.

The Gender of the Person Who Is Drinking

Gender is another important factor to consider when determining how many drinks it takes to reach .08 BAC. Women tend to have a higher percentage of body fat than men, which can slow down the metabolism of alcohol. Women also have lower levels of an enzyme called alcohol dehydrogenase, which is responsible for breaking down alcohol in the liver. As a result, women tend to reach a higher BAC than men after consuming the same amount of alcohol.

The Rate at Which You Are Drinking

The period of time in which you were drinking can also affect your BAC. If you drink several drinks in a short period of time, your BAC will rise more quickly than if you drink the same amount of alcohol over a longer period of time. This is because the liver can only metabolize a certain amount of alcohol per hour, and if you drink faster than your liver can process the alcohol, your BAC will continue to rise.

If You Have Been Drinking on an Empty Stomach

Drinking on an empty stomach can also affect your BAC. When you drink alcohol on an empty stomach, it is absorbed more quickly into the bloodstream because there is no food to slow down the absorption. Eating food before or while you drink can help slow down the absorption of alcohol and reduce your BAC.

A general guideline is that it takes about two standard drinks to raise a 160-pound person's BAC to .08 if consumed within an hour. However, this is not a guarantee and should not be relied upon as an accurate measure.

Implied Consent to BAC Tests in North Carolina

In North Carolina, like in many other states in the United States, drivers are considered to have given "implied consent" to a blood alcohol concentration (BAC) test if they are pulled over for suspicion of driving under the influence (DUI) or driving while impaired (DWI). Implied consent means that by driving on the roads in North Carolina, you are agreeing to take a BAC test if a law enforcement officer suspects you are driving under the influence of drugs or alcohol.  

The implied consent law in North Carolina applies to three types of BAC tests: breath, blood and urine tests. Law enforcement officers are required to follow specific procedures when administering these tests, including providing written notice of the consequences of refusing to take a test. If a driver refuses to take a BAC test, their driver’s license will be suspended for a year and they will not be eligible for a limited driving privilege—for instance, to drive to work—for six months.

Consult a Lawyer Right Away if Charged with DWI

Drivers in North Carolina who are caught with a BAC of .08 or higher can face serious legal consequences, including fines, license suspension and even jail time. An experienced DWI attorney at Morrow Porter Vermitsky & Taylor can help determine a defense strategy. Even if a driver takes a BAC test and their results are above the legal limit of .08, the individual may still be able to challenge the stop, arrest, or validity of the test in court. Factors such as the calibration of the testing equipment, the qualifications of the administering officer and the handling and storage of the test sample may all be called into question.