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 Indiana, the state enforces a zero-tolerance policy for drivers under the age of 21 regarding alcohol consumption and driving. The legal limit for blood alcohol concentration (BAC) for these underage drivers is .02, which is significantly lower than the .08 limit for drivers of legal drinking age. If an underage driver is found operating a vehicle with a BAC of .02 or higher, but less than .08, they can be charged with Operating a Vehicle with a BAC of at least .02 but less than .08 (a Class C infraction), which is a violation of Indiana's zero-tolerance law. However, if the underage driver's BAC is .08 or higher, they can be charged with Operating While Intoxicated (OWI), which is the equivalent of a DUI/DWI charge for adults. This charge can be based on per se intoxication, meaning the BAC alone is sufficient evidence of intoxication, or on common law intoxication, where the charge is based on an officer's observations and belief that the driver was impaired. Penalties for underage DUI/DWI in Indiana can include fines, license suspension, and mandatory attendance in an alcohol education program, among other consequences.