What “driving under the influence” means
Driving under the influence means a person is operating a vehicle while intoxicated or impaired by alcohol, a drug, or an illegal substance. To fully understand the meaning of this, it’s important to examine what exactly “operating a vehicle” means, how laws define “under the influence,” and what drugs and substances fall under that purview.
Operating a vehicle
The exact wording of DUI laws varies state by state, but to “operate a vehicle” means to be in physical control of a vehicle — or, as Texas law explains it, “a device in, on, or by which a person or property is or may be transported or drawn on a highway” — in a public place.
Many times, “operating a vehicle” also includes driving a boat, an airplane, or another mode of transportation. Some state laws separate DUI charges by mode of transportation. For example, boating while intoxicated, or BWI, is a separate criminal offense in Texas.
Under the influence
“Under the influence” means that recent use of alcohol or recreational or prescription drugs has impaired a driver’s normal faculties. In Florida, this even includes nitrous oxide, and in Illinois, medical marijuana qualifies.
In terms of alcohol, every state sets a blood alcohol concentration (BAC) level that amounts to being “under the influence of alcohol” in that jurisdiction. Any person found to have a BAC of that level or higher is considered legally intoxicated. In most states, the BAC limit is 0.08.
DUI/DWI laws by state
Every state has its own laws regarding driving under the influence, and they also have different names for these charges. Most often, DUI or DWI is used, but in some states, it may also be OVI (operating a vehicle impaired), OWI (operating while intoxicated), or OMVI (operating a motor vehicle impaired).
Here’s a look at how the laws break down by state and what each state calls it.
*Indicates a state has a zero-tolerance law for drivers younger than 21 and language such as “any measurable amount of alcohol in the blood” is used.