What's the difference between OWI and DUI?
States use different terms to identify the crime of operating a motor vehicle when under the influence of alcohol, and while in some states, terms like DUI (driving under the influence) and OWI (operating while intoxicated) may actually have concrete legal distinctions, for the most part, the terms are used interchangeably. In some cases, states have adopted one term or another because of favorable semantic associations.
When there is a concrete difference
When you are pulled over for suspicion of driving drunk, officers usually perform a series of checks to determine whether or not you are fit to drive. These may include physical or mental tasks known as a field sobriety test, as well as observational evidence like the odor of alcohol, redness in the eyes and other common indications of intoxication. Finally, officers may perform an on-site breathalyzer test.
The legal limit for driving under the influence of alcohol in the United States is .08 for the average motorist. However, this does not mean that you cannot be charged with a DUI if you blow under a .08. In some states, lawmakers have used breathalyzer results to establish a distinction between DUI and OWI. Typically, OWI is considered a lesser charge. If you exhibit some signs of intoxication but have a BAC of .05, police may charge you with OWI as opposed to DUI, which is a harsher charge reserved for those whose BAC is .08 or higher.
When there is a subtle difference
In some cases, lawmakers have adopted or evolved the language of drunk driving laws to account for nuances in the crime. In Iowa, for example, laws exclusively use the term OWI to account for holes in the language of DUI.
If charged with a DUI, in principle, a defendant could contend that he was not actually driving the car at the time of his arrest - if he is unconscious in a parked car, for example, or struggling to put his keys in the ignition.
By using the term OWI, lawmakers replace the word "driving" with "operating," and can cover their bases, legally speaking.
Where there is no difference
In many states, there is no difference between a DUI and an OWI charge, and the terms are used interchangeably. Penalties for one will often be the same for the other, and legislation relating to look-back periods and misdemeanor and felony distinctions is the same.