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 New Jersey, 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 legal drinking age of 21, New Jersey enforces a zero-tolerance policy, where a BAC of .01% or more can result in a DUI charge. This is stricter than the .02% limit mentioned for most states. Additionally, New Jersey has an implied consent law, meaning that if you drive on New Jersey roads, you have agreed to submit to a breathalyzer test if a police officer suspects you of drunk driving. Refusal to take the test can result in penalties. For those with a BAC of .10% or higher, the penalties may be more severe, and for a BAC of .15% or higher, an ignition interlock device is mandatory.