BAC Testing Laws in North Carolina

Driving while impaired (DWI) is a serious conviction that can result in multiple penalties. For a person to be convicted however, North Carolina law enforcement must test their BAC and prove that they were, in fact, under the influence of drugs or alcohol.

In North Carolina, drivers over 21 are considered to be driving while intoxicated if their BAC is 0.08% or above. Additionally, commercial vehicle drivers can be charged with DWI if their BAC is 0.04% or above and a “zero tolerance” law applies to underage drunk drivers.

Proof of intoxication is typically obtained by conducting a blood alcohol content (BAC) test using one of three methods. But, before we review these methods, it is important to understand North Carolina’s implied consent law.

Implied Consent Law in North Carolina

In North Carolina, if a police officer asks you to take a BAC test, you are obligated to agree. You still have the option to refuse to take a blood-alcohol test, but doing so will mean immediately losing your license, potentially for up to one year.

Whether you refuse a BAC test is up to you. What is most important is that you do not risk incriminating yourself by saying anything to the police officer about whether you’ve been drinking. Remember, you have a right to remain silent, and you should exercise that right until you are able to speak to a North Carolina DWI attorney.

BAC Breath Test

In North Carolina, police officers use breathalyzers to conduct breath tests. The accused is asked to exhale forcefully into the mouthpiece and the device measures the alcohol that’s detected on their breath.

Breathalyzer tests are convenient, portable, and easy to administer, so it’s no surprise that this is the most common way police test a suspect’s BAC. Though they’re most commonly used during DWI arrests, police officers can also give breathalyzer tests at DWI checkpoints. Additionally, an officer can request a breath test during a traffic stop or at an accident scene if they have reason to believe alcohol use was a contributing factor.

Breathalyzer Test Rights

Despite the rigidness of the implied consent law, there are rules police must follow during a breathalyzer test that are designed to protect the suspect’s rights. For instance, the suspect must be observed for a minimum of 20 minutes before being given a breathalyzer test.

Suspects are also entitled to have a witness present, and the arresting officer must allow 30 minutes for the witness to arrive before administering the breathalyzer. The officer giving the test must be trained in how to do so. Finally, for breathalyzer results to be admissible in court, the officer must give two tests and the results of the tests must be within 0.02% of each other.

Breathalyzer Accuracy

It’s important to note that, while breathalyzer tests are fairly accurate, they aren’t the most accurate way to test BAC. This is because physical differences between people and environmental factors can both affect a breathalyzer reading. But these aren’t the only reasons breathalyzer tests can be inaccurate.

There are a variety of unique circumstances that can cause a breathalyzer to indicate that someone is more intoxicated than they actually are. For instance, vomiting within 20 minutes of taking the test can cause an exaggerated reading. Recently ingested medicines, mouthwashes, and breath fresheners that contain alcohol can also cause false readings. Additionally, a malfunctioning or poorly calibrated breathalyzer can skew test results.

Despite all of this, breathalyzer test results are considered accurate enough to use in court to achieve a conviction. If you suspect that your breathalyzer test results were inaccurate, you should contact Mulligan Attorneys,. We may be able to help determine whether the circumstances surrounding the breathalyzer test could have resulted in a false reading.

BAC Blood Test

BAC blood tests are much more difficult to administer, which is why they’re used far less often than breathalyzer tests. Typically, a blood test is only used in scenarios where the suspect is unable to use a breathalyzer.

For instance, if the suspect has a diagnosed medical condition or if they were just injured in an accident, they may not be physically capable of blowing into a breathalyzer machine. An officer might also choose to run a blood test if they have reason to believe the suspect is under the influence of drugs instead of alcohol.

Blood Test Rights

Suspects who don’t agree to allow a blood test are subject to the punishments associated with implied consent law. That said, even those who refuse blood tests may be forced to give a sample. Under the Fourth Amendment, law enforcement may obtain search warrants that allow them to “search” a person’s blood.

Law enforcement can also require you to give blood if they cite exigent circumstances. This allows your blood to be “searched” on the basis that the findings may disappear with time. Under exigent circumstances, police are not required to have a search warrant to conduct a blood test.

Blood Test Accuracy

Blood tests tend to be the most accurate way of determining how much alcohol or drugs are in a person’s system. That said, there are many ways the results can be skewed, as human error can play a big role in destroying the validity of blood test results.

For example, blood samples that aren’t stored properly can coagulate and provide an inaccurate reading. The person(s) handling the sample can affect readings if they don’t properly sterilize their equipment or possess the knowledge to accurately perform the blood draw. Finally, blood samples can also be easily contaminated or swapped with other samples.

BAC Urine Test

Urine tests may be used when it is not possible to conduct a blood or breath test. Police officers may also request urine samples to validate the results of a breath test or if they suspect the influence of drugs. Urine tests are the best way to detect all kinds of drugs, from narcotics to cannabis.

Urine Test Rights

As with the other two forms of BAC testing, implied consent is a factor with urine tests. You can refuse to give a sample, but you will be subject to the same punishment of losing your license for up to one year.

Urine Test Accuracy

Testing urine is the least accurate way to determine someone’s blood alcohol content. Plus, since urine samples are handled and stored much like blood samples, they’re prone to human error and contamination.

Urine also isn’t a great way to determine BAC because it can take a couple of hours for alcohol to show up. Additionally, traces of alcohol can be found in urine for up to 24 hours after consumption. Finally, small amounts of alcohol in food and medicine can result in misleading BAC readings.

At the end of the day, hiring a DWI lawyer is the best way to protect yourself if you’re accused of driving while intoxicated in North Carolina. At Mulligan Attorneys,, we can help assess whether a breath, blood, or urine test has been contaminated or misinterpreted; and we know how to prove our point in court. Let us help you through this difficult time. Call us at 910-763-1100 to schedule your consultation.