DUI stands for
Driving Under the Influence.
DWI stands for either
Driving While Intoxicated or
Driving While Impaired.
Another term that is sometimes used is
Operating While Impaired (OWI).
All these terms relate to driving after consuming alcohol or drugs. The drugs don't have to be illegal for a DUI to be issued - they can be illegal narcotics, over the counter medication, or prescribed medication.
Depending upon the
state in which you are the severity of the offense may vary.
In some states, the drunk driving laws differentiate between a DUI and a DWI, where the DUI is a lesser charge. In these states, a DUI usually signifies a lesser degree of intoxication, which is determined by a person’s blood alcohol level at the time of arrest.
Sometimes, states will allow the charges of a DWI to be reduced to a DUI. In the case of a reduction from a DWI to a DUI, certain conditions typically must be met, such as the incident being a first offense, the defendant’s display of remorse for the action, and a blood alcohol level that was not drastically over the legal limit.
For example, the state of New York differentiates between DWI and DUI by establishing a blood alcohol level of .08 as the legal limit for DWI. If a person has a blood alcohol level of .07, the charges may be reduced to a DUI, which carries a lesser punishment.
Some states (like Virginia and New Jersey) do not recognize any difference between a DUI and a DWI. As far as the laws of these states are concerned, any blood alcohol level over the specified limit is a crime that will be punished in the same manner.
In Minnesota, on the other hand, there is technically no such thing as a DUI because they only use the term DWI.
In some states, the terms DUI and DWI are used to indicate whether a person was driving impaired under the influence of drugs or alcohol. In this case, DUI is reserved for illegal drugs.
The distinction for the federal government is drawn based on severity. A DWI is issued when the blood alcohol content (BAC) is over the 0.08 limit, whereas a DUI is a less severe term, given when a persons BAC is under 0.08.