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 Arizona, the state enforces a zero-tolerance policy for underage drinking and driving. This means that any driver under the age of 21 who is found to have any alcohol in their system can be charged with DUI. Arizona law sets the BAC level for underage drivers at 0.00%. If an underage driver is found with a BAC above 0.00% but below 0.08%, they can still be charged with DUI, as Arizona's zero-tolerance law does not permit any level of alcohol for underage drivers. For those under 21 with a BAC of 0.08% or higher, the charges are the same as for adults, which is a per se DUI, based on the state's legal definition of intoxication. Penalties for underage DUI in Arizona can include fines, license suspension, and mandatory alcohol education programs. The specific charges and penalties can be found in Arizona's Revised Statutes, particularly in the sections dealing with motor vehicle operation and DUI laws.