DUI is an acronym for “driving under the influence.” DWI stands for “driving while intoxicated,” or in some cases, “driving while impaired.” The terms can have different meanings or they can refer to the same offense, depending on the state in which you were pulled over.
In any case, DUI and DWI both mean that a driver is being charged with a serious offense that risked the health and safety of himself and others. They can apply not only to alcohol and recreational drugs but also to driving when your prescription drugs impair your abilities. It’s also important to understand that one is not worse than the other and that both can have a big effect on your life.
Use of Terms DUI vs. DWI Differ From State to State
Depending on state law, the two terms are both used to describe impaired or drunken driving. Some state laws refer to the offense of drunken driving as a DUI while others call it a DWI.
It gets tricky when states use both terms. Quite often, they will refer one to alcohol and the other to impairment by drugs or an unknown substance and the meaning can flip-flop from state to state. In some states, DWI refers to driving while intoxicated of alcohol with a blood alcohol content (BAC) over the legal limit, while DUI is used when the driver is charged with being under the influence of alcohol or drugs.
In other states where both terms are used, DWI means driving while impaired (by drugs, alcohol, or some unknown substance), while DUI means driving under the influence of alcohol. It’s best to check the definitions of the state you’re in.
OUI and OWI
There are other acronyms for drunk driving. OUI, or “operating under the influence,” is used in only three states: Maine, Massachusetts, and Rhode Island. OWI is an acronym for “operating while intoxicated” which is used in some jurisdictions.
The “operating” distinction encompasses more than just driving the vehicle. Even if the vehicle is stopped and not running, someone can be charged with operating under the influence.
Blood-Alcohol Concentration Isn’t the Only Factor in Determining Impaired Driving
Any of these charges mean the arresting officer has reason to believe the driver is too impaired to continue to drive. In some jurisdictions, drivers can be charged with impaired driving (or driving under the influence) even if they do not meet the blood alcohol concentration levels for legal intoxication.
For example, if you fail a field sobriety test or otherwise show signs of impairment, you can be charged with driving while impaired even if your blood-alcohol concentration is under the legal limit of 0.08.
Drugged Driving Is Impaired Driving
If you appear to be impaired by the arresting officer, but your breathalyzer test shows that you are not under the influence of alcohol, he may suspect that you have been using drugs and this is impairing your driving ability. These include prescription and nonprescription medications in addition to illegal drugs. The officer can call a Drug Recognition Expert (DRE) to the scene—or he may be one himself—to perform a series of tests.2
If the DRE officer’s multi-step evaluation process determines that you are indeed under the influence of drugs, you can be charged with DWI or DUI. The charge depends on what the state calls the offense of drugged driving.