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 Michigan, the terms Operating While Intoxicated (OWI) and Operating While Visibly Impaired (OWVI) are used to describe offenses that involve operating a vehicle while under the influence of alcohol or drugs. Michigan law defines OWI as operating a vehicle with a Blood Alcohol Concentration (BAC) of 0.08% or higher, which is the per se intoxication limit. For commercial drivers, the BAC limit is 0.04%, and for drivers under the age of 21, any BAC of 0.02% or more can lead to an OWI charge under Michigan's Zero Tolerance Law. OWVI, on the other hand, can be charged when a person is visibly impaired by alcohol or drugs, regardless of their BAC level. Penalties for these offenses can include fines, imprisonment, community service, and driver's license suspension or revocation. Enhanced penalties may apply for high BAC levels (0.17% or more) or for repeat offenders. It's important to note that while some states differentiate between DUI and DWI, Michigan primarily uses the term OWI to encompass the criminal offense of operating a vehicle while intoxicated by alcohol or drugs.