DUI Dictionary

APS, or Administrative Per Se:

In California as with many other states, there are two separate cases that arise from a single drunk driving arrest: the court case,
and the Administrative Per Se, or A.P.S. case, with the Department of Motor Vehicles. In cases where someone is arrested for DUI the DMV will take an
“administrative action” against the driver. Note: The DMV only allows you Ten days to set a hearing: that
is why it is so important to contact a lawyer right away.


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


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.


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


Blood alcohol content.


Breath alcohol level.


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.


Usually, ability to exert control over the vehicle.
Officers DO NOT need to observe someone driving in order to arrest them for DUI. Circumstantial evidence of driving is typically sufficient.
Driver’s License Suspension: The temporary withholding of driving privileges.

Drunk Driving:

A general reference to those criminal cases that are called DUI, DWI, OUI, OWI, DUII, DWAI, or other acronyms.


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.


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


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.


Driving while under the influence is a phrase that is infrequently used to refer to drunk driving cases. When
this acronym is used, it refers to driving under the influence of alcohol, driving under the influence of drugs, or driving
under the influence of a combination of alcohol and drugs.


Those factors that can operate to increase the punishment in a drunk driving, DUI, DWI, OUI, OWI, or related driving under the influence case.
These enhancements may include driving above a certain speed while DUI, having minors in the car while drunk driving,
having a BAC above a certain level (.20, for example), refusing to take a chemical test after being arrested for DUI,
being involved in a traffic accident while DUI or DWI, or having prior convictions for DUI, DWI, or a related drunk driving offense.

Epileptic Nystagmus:

Nystagmus evident during an epileptic seizure.


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.)


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.

High BAC:

Threshold blood alcohol content for which maximum penalties and fines may apply, even
on a first offense. In California, the court may consider a BAC of .20 as a special factor in imposing
enhanced sanctions and determining whether to grant probation and / or
ordering an ignition interlock device be installed for up to three years. In counties with licensed alcohol education/counseling program,
offenders placed on probation with high BAC must participate in program for at least six months vs. three months.

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:

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 100 ml of blood). The
device is connected to the engine’s ignition system.

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.


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 (NHTSA):

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.

Not Guilty:

The verdict you hope to hear in your DUI, DWI, or drunk driving case.


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


Movement of the eyeball.

Odor of alcohol on breath:

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.


to move back and forth at a constant rate between two points.

PAS test:

Preliminary Alcohol Screening test.

Pathological Disorder:

Disruptions of the normal functions of organs of the body due to disease, illness, or damage.

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.


The alcohol concentration is higher in the blood than in the vestibular system.


The alcohol concentration is lower in the blood than in the vestibular system.

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 provision 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.


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.

Southern California Research Institute (SCRI):

A research organization that conducted the first two research studies that eventually produced the standardized field sobriety test battery. SCRI has conducted subsequent field sobriety test validation studies as well as drug recognition evaluation studies.

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.


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.


A motor vehicle, car, truck, motorcycle. In some states, a DUI, DWI or drunk driving conviction can result from driving a bicycle, riding a horse, driving a snowmobile, or even a motorized wheelchair.

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 California, 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.

Wet Reckless:

Plea to a charge of reckless driving which was “alcohol related.” A wet reckless results from a plea bargain to reduce a charge of drunk driving. There are several reasons for such a reduction, including a borderline blood alcohol level. The result is a lower fine, no jail time and no record of a drunk driving conviction, but if there is a subsequent drunk driving conviction the “wet reckless” will be considered a “prior” drunk driving conviction. A wet-reckless can be especially important to anyone who holds a professional license, since it is only reported on a criminal record as a reckless driving. It is vital that you consult with a criminal defense DUI lawyer before accepting any such plea.


A person who can provide testimony on behalf of the prosecution or DUI defense.

Zero Tolerance BAC:

Allowable blood alcohol content for minors. In California, this law states that it is against the law to drive with a blood alcohol concentration (BAC) of .01% or higher if you are under 21 years of age. Your BAC is measured by a test given to you by a police officer. Under this law, on your first offense, your driving privilege will be suspended for one year if:
your BAC is .01% or higher, or you refuse to take the preliminary alcohol screening (PAS) test, or you fail to complete the PAS test

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