What does DUI stand for? It stands for driving under the influence, the legal term many US states use for operating a vehicle while impaired by alcohol, drugs or both. The phrase "under the influence" covers legal medicines and other substances too, not only beer, wine and liquor.
You will see the letters on traffic tickets, court calendars, news reports, insurance forms and highway safety signs. Some states use other names for the same kind of offense, such as DWI or OWI, which is why the terms are easy to mix up.
Quick facts
Stands for
Driving under the influenceType
Initialism, said D U ICovers
Alcohol, illegal drugs, some prescription and over the counter drugsCommon adult BAC limit
0.08 percent in most statesSeen in
Traffic court, police reports, news, insurance and job formsPlural
DUIsRelated terms
DWI, OWI, OUI, BAC
What does DUI stand for in legal terms?
Broken into its parts, the phrase is simple:
- D, Driving: in many states this also covers being in physical control of a vehicle, such as being parked in the driver seat with the motor on.
- U, Under: affected by.
- I, Influence: of alcohol, drugs or a mix that lowers a person's ability to drive safely.
Each state writes its own law, so the exact wording, the vehicles covered and the penalties differ. In general, a person can be charged in two ways: by being impaired in fact, or by having a blood alcohol level at or above the legal limit, even without visible signs of impairment.
The BAC limits behind most DUI charges
BAC means blood alcohol concentration, the share of alcohol in the bloodstream. Common US limits look like this:
| Who is driving | Common cutoff | Detail |
|---|---|---|
| Drivers age 21 or older | 0.08 percent | Utah uses a lower 0.05 percent limit |
| Commercial vehicle drivers | 0.04 percent | Applies while driving a commercial vehicle |
| Drivers younger than 21 | 0.02 percent or lower | Known as zero tolerance laws |
Staying under these numbers is no guarantee, since an officer who sees signs of impairment may still make an arrest. Holders of a CDL face stricter rules because of the size of the vehicles they drive.
DUI vs DWI, OWI and other state terms
The letters change from state to state, but they all point to impaired driving. A few states keep two separate charges, one more serious than the other.
- DWI: driving while intoxicated, or while impaired, depending on the state.
- OWI: operating while intoxicated. "Operating" can reach further than "driving."
- OUI: operating under the influence.
- DUII: driving under the influence of intoxicants.
- BUI: boating under the influence, for boats and personal watercraft.
When you read a news story or a form, use the term that state uses. The meaning in everyday talk is the same.
What happens after a DUI stop
Steps vary by state, but a common sequence is a traffic stop, field sobriety tests, a breath test and, after an arrest, a chemical test of breath, blood or urine. Most states have implied consent laws, which say that by holding a license a driver agrees to be tested, and refusing can bring its own license suspension.
Possible results of a conviction include fines, a suspended license, classes, an ignition interlock device that checks breath before the car starts, and in some cases jail. Insurance costs often rise, and a record may show up on background checks. The local DMV handles the license side, separate from the court case.
DUI stands for more than a court term
The letters also appear well outside the courtroom, and the meaning there is the same.
On a highway sign: "Holiday DUI enforcement ahead." Police are running extra patrols to find impaired drivers.
On a job application: "Have you ever been convicted of a DUI?" The employer, often for a driving job, wants to know about past impaired driving convictions.
Safety campaigns use lines such as "Plan a sober ride" alongside the letters to remind people to use a taxi, a ride service or a designated driver.
How to write and say DUI
It is spoken as three letters, "D U I," and printed in all caps with no dots. Use a in front, "a DUI," since D begins with a consonant sound. As a noun it can mean the charge, the arrest or the conviction, so context matters: "He got a DUI" usually means he was charged. More legal and agency letters are on the government acronyms page.
Questions people ask
Can you get a DUI for prescription medicine?
Yes. If a legal medicine affects your ability to drive safely, many state laws treat that the same as other impairment. Read the warning label and ask a pharmacist about driving.
Is a DUI the same as a DWI?
They describe the same kind of conduct, impaired driving. Some states use only one term, while others use both for different levels of the offense.
What BAC counts as a DUI?
For most adult drivers the legal limit is 0.08 percent, and Utah uses 0.05 percent. Lower limits apply to commercial drivers and people under 21.
Can you get a DUI on a bike?
In some states, yes, because their laws cover bicycles or any vehicle. In others the law is limited to motor vehicles, so it depends on where you live.
Does a DUI stay on your record?
A conviction usually stays on a criminal record and on a driving record for years, and in some states for life. Rules for sealing or clearing a record vary, so a lawyer can explain local options.