Dictionary of DWI Terms

Drunk driving arrests, DUI / DWI arrests, cases involving driving under the influence of drugs (DUID), or the combination of alcohol and drugs, all of these cases seem to have their own language.

Indeed, DUI / DWI criminal defense lawyers seem to have their own language. As any criminal defense attorney who concentrates on defending drinking and driving cases will admit, there are special terms which are not readily understood. The following are often-used (and not often easily understood) terms relating to DWI / DUI, drunk driving, drinking and driving, DUID (driving under the influence of drugs) and other related criminal arrests:

Acetone – an organic compound commonly found in the breath that can be improperly read as alcohol by the Intoxilyzer.

Absorption – The taking of alcohol from outside the body into the bloodstream. Peak absorption refers to the highest level of blood alcohol seen before blood alcohol content (BAC) begins to diminish.

Alcohol Gaze Nystagmus (AGN) – Gaze nystagmus caused by the effects of alcohol upon the nervous system.

Arraignment – The initial court proceeding, where someone arrested for DUI / DWI, drunk driving, or any related drinking and driving criminal charge is formally advised of the charges against them, and given an opportunity to enter a plea.

BAC – Blood alcohol content. In most states, alcohol level may be determined by reference to breath alcohol level as well, without having to convert to blood alcohol level.

Breathalyzer – A portable machine utilized by law enforcement to measure the blood alcohol content (BAC) of suspected drunk drivers.

Search our Intoxilyzer records database to see if the unit that was used in your case was functioning correctly.

Burnoff – The ability of the body to metabolize alcohol, and eliminate it from the system through the functioning of the vital organs. The rate of burnoff will vary from person to person, and even be different for the same person depending upon various factors. This is just one of the reasons that retrograde extrapolation is such a difficult task, and why the results are uncertain.

Caloric Nystagmus – A vestibular system nystagmus caused by differences in temperature between the ears, e.g., one ear is irrigated with warm water and the other irrigated with cold water.

Chemical Test – As related to driving under the influence (DUI), a test of the alcohol or drug concentration in a person’s blood. Blood or urine tests are used if other drugs are suspected.

Driving – Usually, ability to exert control over the vehicle. Officers usually need not observe someone driving in order to arrest them for DUI / DWI or any drunk driving arrest. Circumstantial evidence of driving is typically sufficient to establish this element.

Driver’s License Suspension – The temporary withholding of driving privileges. A DUI offender’s license is withheld for a given period, then returned when and if specific conditions have been met.

Drunk Driving – A general reference to those criminal cases that are called DUI, DWI, OUI, OWI, DUII, DWAI, or other acronyms. They generally describe two types of cases: first, where the driver is sufficiently impaired by alcohol, drugs, or a combination of the two, that the driver cannot drive safely. Second, “drunk driving” relates to those cases where someone is above that state’s legal limit, usually .08, no matter how safely the person is driving.

DUI – Driving under the influence. Can either refer to driving under the influence of alcohol, driving under the influence of drugs, or driving under the influence of a combination of liquor and drugs. This is the most widely used acronym for drunk driving cases. The standard for what it means to be under the influence will vary from state to state. It is important to contact a lawyer in your area that knows DUI law if you have been accused of DUI or a related drunk driving offense.

DUID – Driving under the influence of Drugs. For purposes of DUID, the drugs may be legal or illegal, prescribed or otherwise.

DWAI – Driving while abilities impaired. This acronym is used in Colorado to refer to a lesser charge that is related to drunk driving, but does not carry all of the same consequences and punishments. A DWAI conviction, in those few states that offer DWAI, may not be considered a prior conviction for drunk driving purposes in other states. It is important to consult a drunk driving lawyer that is well-versed in this area of the law to ensure your rights are protected.

DWI – Driving while intoxicated, or driving while impaired. Like DUI, DWI can refer to driving while intoxicated or impaired as the result of either drinking alcohol or taking drugs, or both. This is the second most widely used acronym for drunk driving cases. Like DUI, the question of how to define being intoxicated or impaired is at the heart of a drunk driving case in jurisdictions that use DWI. It is critical to consult with a DWI lawyer in your area that understands these sophisticated issues.

Epileptic Nystagmus – Nystagmus evident during an epileptic seizure.

Extrapolation – The method of computing BAC at a given time using physical characteristics of the drinker, the quantity of alcohol consumed, the period of time over which alcohol is consumed, and when the alcohol was last consumed.

Field Sobriety Test (FST) – Any number of tests used by law enforcement officers, usually on the roadside, to determine whether a driver is impaired. Most FSTs test balance, coordination and the ability of the driver to divide his or her attention among several tasks as once. Other tests, such as the horizontal gaze nystagmus test, are used to measure a subject’s impairment level.

Felony drunk driving – Under certain circumstances the misdemeanor offense of driving under the influence of alcohol will be treated as a felony, such as when drunk driving results in great bodily harm or death or where the accused has three or more prior DUI convictions. (Note that certain related charges, such as “wet reckless” driving may count as a prior DUI conviction for this purpose.)

Fixation – ability of the eye to focus on one point.

Gaze Nystagmus – Nystagmus that occurs when the eyes gaze or fixate upon an object or image. Usually caused by a disruption of the nervous system.

Horizontal Gaze Nystagmus (HGN) – Gaze nystagmus that occurs when the eyes gaze or move to the side along a horizontal plane.

Impairment or Intoxication – Those states that refer to Driving While Intoxicated (DWI) or Driving While Impaired (DWI) usually have definitions that are similar to being under the influence. Each state has a different standard, so it is extremely important to contact a drunk driving lawyer in the state where you were arrested.

Ignition Interlock Device – Located inside a vehicle and near the driver’s seat, an ignition interlock device is an in-car alcohol breath screening device that prevents a vehicle from starting if it detects a blood alcohol concentration (BAC) over a pre-set limit of .02 (i.e., 20 mg of alcohol per 100ml of blood). The device is connected to the engine’s ignition system. Many states require that the device be used by those convicted of driving under the influence (DUI).

Jerk Nystagmus – Nystagmus where the eye drifts slowly away from a point of focus and then quickly corrects itself with a saccadic movement back to the point of focus.

License Revocation – A license revocation means your driving privileges have been cancelled. You will likely need to reapply for a driver’s license after a designated length of time.

Motions – Asking the court to do something. Drunk driving defense lawyers will usually file many motions with the court in defending a driver accused of DUI, DWI, OUI, OWI, or a related drunk driving offense. These motions may include discovery motions (to force the prosecutor to turn over evidence), motions to suppress evidence, motions to dismiss the case, and many others.

National Highway Traffic Safety Administration– The agency within the United States Department of Transportation that administers traffic safety programs. NHTSA’s duties include funding studies on field sobriety tests and training law enforcement officers in the administration of the standardized field sobriety test battery.

Natural Nystagmus – Nystagmus that occurs without any apparent physiological, vestibular, or neurological disturbance. Natural nystagmus occurs in approximately 2%-4% of the population.

Neurological Nystagmus – Nystagmus caused by some disturbance in the nervous system.

Nystagmus – An involuntary bouncing or jerking of the eye caused by any number of vestibular, neurological or physiological disturbances.

Odor of alcohol on breath – the most dependably recurring symptom in an officer’s report after stopping someone for suspected drunk driving. While alcohol itself has little or no odor, the odor of the flavorings can be deceptive as to the strength or amount drunk.

One-Leg-Stand (OLS) test – One of the three tests that make up the standardized field sobriety test battery. This test requires a subject to stand on one leg, look at his or her foot and count out loud to thirty. The subject is assessed on the ability to understand and follow instructions as well as the ability to maintain balance for thirty seconds. (post-publication note (August 1999), sentence should read: “…count out loud until told to stop.”)

Optokinetic Nystagmus – A nystagmus evident when an object that the eye fixates upon moves quickly out of sight or passes quickly through the field of vision, such as occurs when a subject watches utility poles pass by while in a moving car. Optokinetic nystagmus is also caused by watching alternating moving images, such as black and white spokes on a spinning wheel.

Pendular Nystagmus – Nystagmus where the eye oscillates or swings equally in two directions.

Per Se Laws – Laws that declare it illegal to drive a vehicle above a certain alcohol level, as measured by a blood or breath test. In most states, the per se limit is .08% or greater. Violating the per se law has nothing to do with one’s ability to drive a car safely; it is based solely on body chemistry. The only question is whether the driver was above the legal limit at the time of driving. NOTE: since breath or blood testing always takes place after the time of driving, it does not directly answer the question of BAL at the time of driving. The alcohol level at the time of testing may be higher, lower, or the same, when compared to the time of driving.

Physiological Nystagmus – A nystagmus that occurs so that light entering the eye will continually fall on non-fatigued cells on the retina. Physiological nystagmus is so slight that it cannot be detected without the aid of instruments and it occurs in everyone.

Positional Nystagmus – Nystagmus that occurs when a foreign fluid is in unequal concentrations between the blood and the fluid in the semi-circular canals of the vestibular system.

Post-Rotational Nystagmus – Nystagmus caused by disturbances in the vestibular system fluid when a person spins around. Post-rotational nystagmus lasts for only a few seconds after a person stops spinning.

Provisional (or Restricted) License – A provisional license typically denies certain license privileges. For instance, in a DUI context, a person with a provisional license will only be allowed to drive to and from work.

Reasonable Doubt – The definition varies from state to state. Before someone may be found guilty of DUI or DWI, the jury (or judge in those states that do not allow a jury trial for drunk driving cases) must be convinced in the defendant’s guilt beyond a reasonable doubt. It represents the highest legal standard in our country; it generally requires an abiding conviction (long-lasting belief) in the truth of each and every element of the charges.

Resting Nystagmus – Nystagmus that occurs as the eye are looking straight ahead.

Retrograde extrapolation – This is the scientific term for the ability to look at someone’s alcohol level at the time of testing, and look backwards to determine what the alcohol level was at the time of driving.

Reckless Driving – Operating a motor vehicle in a dangerous manner, including speeding, weaving in and out of traffic, and similarly hazardous patterns. Reckless driving is one of several potential grounds for increased DUI penalties.

Rising Alcohol Defense – This defense is based on the idea that alcohol levels change over time, as the body absorbs alcohol, reaches a peak level, and then eliminates alcohol. Breath or blood testing is done after driving (sometimes long after); these test results tell us what the alcohol level is at the time of testing, not at the time of driving. The rising alcohol defense is simply that at the time of driving (the critical time in a drunk driving case), the alcohol level was below the legal limit, even if it continued to rise until the time of testing.

Rotational Nystagmus – Nystagmus caused by disturbances in the vestibular system fluid when a person spins around. Rotational nystagmus occurs while the person is spinning.

Saccadic – Movement of the eye from one fixation point to another.

Sobriety Checkpoints – The practice of law enforcement agencies selecting a particular location for a particular time period and systematically stopping vehicles (for example, every fifth car) to investigate drivers for possible DUI / DWI.

Smooth Pursuit – The eye’s course as it tracks a moving image.

Standardized Field Sobriety Test (SFST) – A group of tests selected as the best field sobriety tests to increase the ability of law enforcement officers to detect driver impairment. The results of this battery, usually administered along the roadside, contribute extensively to a law enforcement officer’s decision to arrest a person for impaired driving.

Tolerance – As it relates to DUI / DWI, the ability of a person to adapt and maintain their behavior to disguise the effects of alcohol consumption.

Under the Influence – The precise definition used in court will vary from state to state; however, it will relate to the inability of the driver to operate a motor vehicle with the same caution characteristic of a sober person of ordinary prudence under the same or similar circumstances. It is not necessary for someone to have an alcohol level that is above the legal limit to be under the influence. However, most states do allow a jury to infer or presume that if someone is above the legal limit at the time the test was taken, and if the test was given close in time to the time of driving (within two or three hours), that the driver is under the influence. The manner in which the vehicle is driven is relevant, but not usually determinative in and of itself.

Vertical Nystagmus – Nystagmus that occurs when the eyes gaze or move upward along a vertical plane.

Vestibular System – The system of fluid-filled canals located in the inner ear that assists in balance, coordination and orientation.

Vestibular System Nystagmus – Nystagmus caused by a disturbance in the vestibular system.

Vehicle Impound/Immobilization – In New York, if you are driving with a suspended or revoked license, the vehicle you are driving may be impounded for 30 days and possibly forfeited.

Voir Dire – Jury selection. In those states that allow a jury trial for drunk driving cases, either the lawyers or the judge (or both) will question potential jurors about their background and qualifications to sit as jurors in the case. This process is called voir dire, and is extremely important in defending a DUI, DWI, or related drunk driving case. Both the prosecution and the defense are entitled to fair and unbiased jurors, in those states that allow jury trials in DUI, DWI, or drunk driving cases. Voir dire is the process by which the parties learn about the potential jurors, and determine whether or not the drunk driving case is a proper one for the potential juror to hear.

Walk-and-Turn (WAT) test – One of the three tests that make up the standardized field sobriety battery. This test requires a person to take nine heel to toe steps down a straight line, turn and take nine heel to toe steps back up the line. The subject is assessed on the ability to understand and follow instructions as well as the ability to maintain balance during the instruction stage and walking stage.