DUI Glossary of Terms

The following definitions provide a nice explanation of common terms heard during DUI cases. Of course, a local DUI lawyer can provide you with even more information on these DUI definitions.

To get in contact with a DUI attorney in your area, simply fill out our DUI case evaluation form or call 877-349-1311.


Administrative License Suspension (ALS): automatic suspension of driver's license for refusal of a breath test or BAC content greater than the legal limit of 0.08 percent. This sanction is enforced in addition to any criminal penalties that result from conviction of a DUI charge.

Related Resources:

  • Administrative License Suspension Overview

Alcohol Counseling: treatment for alcohol dependence and alcoholism. Alcoholics Anonymous is probably the most famous alcohol counseling program in the country.

Many counseling programs rely on group therapy and mutual-help to help problem drinkers address the issues underlying their abusive relationships with alcohol.

Alcohol Monitoring Device: Commonly known as SCRAMs (Secure Continuous Remote Alcohol Monitors) bracelet, alcohol monitoring devices are used to track the alcohol consumption of those convicted of alcohol-related offenses like DUI.

The SCRAM bracelet works by recording alcohol content in the sweat from the wearer's skin and transmits data by radio signal to a modem. Monitoring bracelets can be used instead of random sobriety tests or jail time.

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Arrest (DUI Arrest): a person is "under arrest" when held in police custody. A DUI arrest occurs when a police officer detains someone for suspicion of driving under the influence of drugs or alcohol.

A DUI arrest can lead to DUI charges, which must then be handled through the appropriate legal channels.

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Blood Alcohol Content (BAC): a measure of how much alcohol one has consumed. This number is expressed as a percentage and is used to determine impairment per se in many DUI cases. Also referred to as blood alcohol concentration.

Blood alcohol content can be measured by taking a blood sample, and is often approximated by breathalyzer machines. The legal BAC limit for operating a vehicle in the United States is .08%.

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Breath Alcohol Content: the concentration of alcohol in a person's breath. Breathalyzers measure this and use the figure to estimate blood alcohol content.

In some instances, estimates of blood alcohol content based on breath alcohol content are incorrect and can be contested in criminal court.

Breath Test: a test that measures breath alcohol content (or breath alcohol concentration). Breathalyzer machines, which are commonly used to administer breath tests, estimate BAC based on breath alcohol content.

If you're pulled over for suspicion of DUI, you may be asked to submit to a breath test by a police officer. Learn more about breathalyzer tests.

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Breathalyzer: a machine that administers breath tests. Breathalyzers measure breath alcohol content (concentration) and then estimate BAC from that figure. The formula used to convert breath alcohol content to BAC is based on a hypothetical "average person."

If you are asked to blow into a breathalyzer and your measurements (height, weight, muscle-to-fat ratio) are different from those of the "average person," the estimated BAC could be incorrect. Many DUI lawyers have successfully challenged breathalyzer results in court.

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Burden of Proof: the responsibility of proving allegations in a legal context.

In DUI cases, burden of proof has an interesting role. If the person accused of DUI has a BAC reading of .08% or higher at the time of the arrest, the burden of proof lies with the defendant to prove that he or she was not impaired while driving. If the accused has a BAC below .08%, the state must prove that he or she was impaired when arrested.

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Charge/DUI Charge: a formal legal accusation. If you are charged with DUI, the legal system has officially recognized that you are suspected of the crime of driving under the influence of alcohol or drugs.

DUI charges can be met with a plea of guilty, not guilty or, in some states, no contest; not guilty pleas generally lead to courtroom trials, guilty pleas to out-of-court arrangements.

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Conviction (DUI Conviction): proof of guilt in a court of law. When a judge or jury finds a defendant guilty, the defendant is considered convicted of a crime.

DUI convictions can lead to penalties including probation, driver's license suspension, alcohol counseling, jail or prison time, alcohol monitoring, installation of an ignition interlock device and more.

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Defendant: in a court of law, a person charged with a crime.

The defendant is so called because most trials consist of a defense presented to display the innocence of the accused.

Drunk Driving: see DUI.

DUI (Driving Under the Influence): legal term for driving a motor vehicle while under the influence of any intoxicating substance, including drugs and alcohol. Nationally, .08% is the legal blood alcohol limit, meaning that operating a motor vehicle at or above .08% BAC could lead to charges of DUI.

In some areas, DUI is referred to as DWI, OUI, OWI and drunk driving. Learn more about DUI FAQ.

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DUI Penalty: consequence for a DUI conviction.

DUI laws are different in every state, but common penalties include license suspension, alcohol or drug counseling, fines, jail time and classification of subsequent DUIs as felony offenses. Learn more about DUI Penalties.

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DWI: Driving While Intoxicated. See DUI.

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Evidence: facts or representations of facts presented in court as proof of guilt or innocence. Judges and juries make decisions of guilt or innocence based on evidence presented.

Evidence in DUI cases often includes testimony from arresting officers, breathalyzer test results, results from blood tests (if any were taken) and more. Challenging such evidence is often part of a DUI lawyer's defense strategy. Learn more about building a DUI defense.

Expungement of DUI: a process that can partially clear your criminal record after a DUI conviction. In many cases, a DUI expungement is available after you've successfully completed probation and served out the probationary period.

In most states, a DUI expungement allows you to withdraw your plea of guilty or no contest, re-enter your plea of not guilty and have your DUI case dismissed. A DUI expungement can be valuable for applying for jobs-employers are not allowed to hold the DUI charge against you.

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Felony DUI: classification of a DUI charge as a felony offense. In most states, DUI convictions can range in severity from misdemeanors to felonies.

In some states, multiple DUI convictions lead to a more severe criminal classification of the crime; such a policy is considered one DUI penalty.

Field Sobriety Test: non-mechanical tests administered at the time of a DUI arrest to assess a suspect's level of intoxication. In most states, participation in field sobriety tests is mandatory.

In 1980, the National Highway Transportation Safety Administration (NHTSA) developed a standardized model for administering field sobriety tests. This model must be followed by all police officers. Evidence from field sobriety tests was relied upon more heavily in DUI cases before the introduction of the breathalyzer. Learn more about Field Sobriety Tests.

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Guilty Plea: in criminal court (where DUI cases are tried), an affirmative answer to the charges against the defendant. In other words, those who plead guilty to DUI charges basically acknowledge that they drove under the influence.

In DUI cases, a defendant who pleads guilty waives his right to a criminal trial and can be directly sentenced by a judge.

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Ignition Interlock Device: a breathalyzer attached to a car's engine, used to prevent drunk driving. The ignition interlock works by testing the driver's breath alcohol content before allowing the car to start; if the BAC calculated is above a set limit, the engine is locked and the car won't start.

Ignition interlock devices are becoming more popular across the country. In some states, ignition interlock devices are mandated for even first time offenders. Like many remote testing devices, ignition interlock systems record information from each test that can be accessed by administrators for analysis. Learn more.

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Implied Consent: in 49 states, implied consent statutes outline penalties for anyone who refuses certain tests used to detect DUI. In many states, refusing a breathalyzer or blood alcohol test can lead to driver's license suspension.

Some drivers who have been drinking choose to refuse sobriety tests, hoping that the penalties for refusal will be lower than penalties for a DUI conviction. There has been a legislative move in many states, though, to increase penalties for refusing sobriety tests.

Injury Liability: legal responsibility for injuries caused to a person.

Assignment of liability for a victim's injuries (in the form of medical bills, perhaps) could be a penalty of a DUI conviction.

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License Suspension: sometimes a penalty for DUI convictions. Administrative License Suspension (ALS), also known as administrative license revocation, refers to temporary suspension of a driver's license by a police officer at the scene of a suspected DUI.

Several court cases have dealt with the constitutionality of ALS and ALR measures, but driver's license suspension for actual convictions is generally accepted throughout the United States.

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MADD: Mothers Against Drunk Driving. MADD is a national organization that was founded in 1980 by the mother of victim of a deadly drunk driving accident. Since its inception, it has successfully pushed for stricter drunk driving laws, promoted the use of designated drivers and focused on educating Americans about the dangers of driving under the influence of alcohol. Official MADD site.

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No Contest Plea: in criminal court (where DUI cases are tried), this plea allows the defendant to neither affirm nor deny the charges against him. Also known as "nolo contendere" plea.

Some states do not permit "no contest" pleas in court. For information about your options, you should consult a DUI lawyer.

Not Guilty Plea: in criminal court (where DUI cases are tried), a negation of the charges against the defendant. In other words, those who plead not guilty effectively agree to proceed to trial to have a jury or judge decide their guilt based on evidence presented.

Not guilty pleas in DUI cases lead to trials (see "burden of proof").

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OUI: Operating Under the Influence. See "DUI."

OWI: Operating While Intoxicated. See "DUI."

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"Per Se" Limit: literally, "in itself." This refers to the national BAC limit of .08%, and means that it is illegal in itself for drivers 21 years old and older to have a blood alcohol concentration of .08% or higher while driving.

Because of differences in body mass and tolerance, though, not every driver has the same impairment limit. At trial, the state can offer evidence to prove that someone with a BAC lower than the .08% per se limit was impaired while driving. Similarly, the defense can offer evidence to prove that someone with a BAC higher than .08% was not impaired while driving. See "burden of proof."

Plea Bargain: used in many criminal cases in the United States to speed the criminal justice process. In most plea bargains, the defendant agrees to plead guilty to charges less serious than those originally brought in exchange for a known sentence that's usually shorter than what a jury could have awarded for a conviction. This also allows the court system to move more quickly than it could with only trials.

In DUI cases, plea bargains sometimes include dropping felony DUI charges, offering shorter jail sentences, allowing probation and more.

Probation: criminal penalty that acts as an alternative to incarceration (prison time). During a period of probation, many criminals must check in with a probation officer at regular intervals and follow a strict code of behavior to avoid more serious penalties.

Those on DUI probation may be required to wear alcohol monitoring devices or submit to random tests to prove sobriety.

Property Liability: legal responsibility for damage caused to property.

Damaging another driver's car or knocking over a mailbox during a drunk driving incident could lead to property liability for those items as part of a DUI conviction.

Prosecutor: the attorney who attempts to prove that a defendant is guilty of a crime.

In DUI cases, the state acts as the prosecutor and attempts to prove that the defendant was impaired during the time of the arrest.

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Sobriety Checkpoint: also called DUI checkpoints, these are places where police officers are stationed for the specific purpose of detecting drunk drivers. Permitted in all but 11 states, sobriety checkpoints allow police officers to check drivers at random for signs of intoxication and impairment.

Sobriety checkpoints are somewhat controversial, since some studies have found them to be less effective than normal police cruising, and even detrimental to the overall rate of alcohol-related accidents.

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Vehicular Homicide: crime in which negligent operation of a motor vehicle or driving while committing a non-felony offense leads to death.

Basically, vehicular homicide laws allow courts to view motor vehicles as potentially deadly weapons. Driving under the influence of alcohol or drugs can certainly be considered negligent operation of a vehicle, and can lead to charges of vehicular homicide if someone is killed.

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Warrant/Arrest Warrant: authorization by a court (issued on behalf of the state) for the arrest of an individual.

If a DUI suspect does not show up for the court date scheduled, the state can issue a warrant for the suspect's arrest.

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Zero Tolerance: policy generally applied to drivers younger than 21, who are not legally allowed to drink alcohol in the United States. Basically, zero tolerance policies allow for DUI penalties for underage drivers with any alcohol in their systems (some states have a .01% limit, some .02%).

Zero tolerance policies punish underage drinkers with very low BACs for drinking as well as driving after drinking. Learn more.

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