Blood Alcohol Concentration (BAC) refers to the percent of alcohol (ethyl alcohol or ethanol) in a person’s bloodstream and is usually determined by a breathalyzer test or a blood test when the police suspect a driver of being intoxicated. For example, a BAC of .10% means that the person’s blood supply contains one part alcohol for every 1,000 parts blood.

In most states a driver is considered legally intoxicated if their BAC is .08 or higher. This BAC level is generally prescribed by a state statute (a law enacted by the state legislature) and creates a presumption of intoxication—also known as per se BAC because it is intoxication by definition. In Utah, the per se BAC level is .05.

Most states have a zero-tolerance BAC level of .02 for drivers under the legal drinking age (usually 21) that will result in a DUI/DWI charge. And most states also have an enhanced penalty or aggravated DUI/DWI charge for drivers whose BAC is .15 or higher—with a few states placing this aggravated or enhanced-penalty DUI/DWI BAC level at .16 to .20.

In North Dakota, the legal limit for Blood Alcohol Concentration (BAC) for drivers aged 21 and over is .08%, in line with the majority of states. This means that a driver with a BAC of .08% or higher is considered legally intoxicated and can be charged with Driving Under the Influence (DUI). For drivers under the age of 21, North Dakota enforces a zero-tolerance policy, where any detectable BAC above .02% can result in a DUI charge. This is to discourage underage drinking and driving. Additionally, North Dakota has enhanced penalties for what is often referred to as an 'aggravated DUI,' which applies to drivers with a BAC of .16% or higher, doubling the standard legal limit. These enhanced penalties can include longer jail time, higher fines, and extended license suspension periods.