DUI (driving under the influence), DWI (driving while intoxicated), and OWI (operating while intoxicated) are similar criminal offenses that involve the operation of a motor vehicle, electric vehicle, or sometimes an otherwise-powered vehicle—including boats, aircraft, and bicycles—by an operator who is under the influence of or intoxicated by alcohol or drugs. Per se (pronounced purr-say) intoxication is intoxication by definition—as defined in the state’s statutes by blood alcohol concentration (BAC) of .08 or more (.05 in Utah). And even if a person is not per se intoxicated, they may be intoxicated by not having the normal use of their mental or physical faculties (abilities), for example, and may be charged with a criminal offense.

In some contexts the terms DUI and DWI are used interchangeably, with some states using one term and other states using the other term to define what is essentially the same criminal offense. But in some states both criminal charges are available and there is a legal distinction between them.

For example, in some states with both criminal offenses, DUI is the criminal offense of operating a vehicle under the influence of prescription or recreational drugs, and DWI is the offense of operating a vehicle while intoxicated by alcohol. In some states DWI refers to per se intoxication when the driver’s BAC is above the threshold defined by statute—.08 (.05 in Utah)—and DUI is a criminal offense charged when the police officer believes the driver is under the influence of alcohol, despite the driver’s BAC being below the statutory threshold of .08. And in some states DUI is a separate offense for drivers under the legal age of drinking (21) who have some alcohol in their system, but less than a .08 BAC.

These and other similar alcohol-related operating offenses—including aggravated or enhanced forms of these offenses—vary from state to state in their definitions and potential punishments and are generally located in a state’s statutes—often in the penal code or criminal code.

In Arizona, DUI (driving under the influence) is the term used to describe the offense of operating a motor vehicle while impaired by alcohol or drugs. Arizona law sets the blood alcohol concentration (BAC) limit at 0.08% for drivers of legal drinking age, which is in line with the per se intoxication standard. However, for drivers under the age of 21, any detectable amount of alcohol can result in a DUI charge, reflecting a zero-tolerance policy. The state does not use the term DWI (driving while intoxicated) or OWI (operating while intoxicated) as separate offenses; DUI encompasses all forms of impaired driving. Penalties for DUI in Arizona can include fines, jail time, mandatory education or treatment programs, and the installation of an ignition interlock device. The severity of the punishment typically increases with the BAC level and the number of prior offenses. Arizona also has aggravated DUI offenses, which apply in situations such as having a third DUI within 84 months, DUI with a suspended license, or DUI with a passenger under 15 years old, which carry more severe penalties.