Most states have a zero-tolerance (or near zero-tolerance) blood alcohol concentration (BAC) level of .02 for drivers under the legal drinking age (usually 21) that will result in a DUI/DWI charge. Some states set the BAC level at which a minor may be charged with DUI/DWI at .05. And some states will charge a minor driving a vehicle with a BAC of less than the state’s per se intoxication level (usually .08) with violating a zero-tolerance law such as driving while ability impaired (DWAI)—but will charge a minor with a BAC of .08 or more with per se (pronounced purr-say) DUI/DWI based on the state’s BAC-level definition of intoxication—or, in the absence of a chemical test of blood, breath, or urine, will charge the minor with common law DUI/DWI based on the police officer’s belief the minor was driving while intoxicated.

DUI/DWI criminal offenses, punishments, and terms used for underage DUI/DWI vary from state to state. These laws are generally located in a state’s statutes—often in the penal code or criminal code.

In Tennessee, the state adheres to a zero-tolerance policy for underage drinking and driving. The legal drinking age is 21, and for drivers under this age, the state enforces a blood alcohol concentration (BAC) limit of .02 for driving under the influence (DUI) charges. If an underage driver is found to have a BAC of .02 or higher, they can be charged with DUI. For those with a BAC of .08 or above, which is the standard per se intoxication level for adults, the charges are the same as for adults driving under the influence. The penalties for underage DUI in Tennessee can include fines, license suspension, and possible jail time, among other consequences. The specific laws governing DUI/DWI for minors are found in Tennessee's statutes, particularly within the sections pertaining to motor vehicles and traffic regulations.