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Commonly Used DWI Terms In Missouri

At the law firm of Travis Noble, P.C., in St. Louis, Missouri, we believe that people accused of DWI need to understand the legal and factual issues that affect their cases. In the interests of educating our clients and the general public, we present the following glossary of DWI terms.

You probably have questions about your situation. In a free consultation, an attorney at our firm can review your case and discuss possible defense strategies with you. Call us today at 314-450-7849.

Administrative hearing

A hearing with a Department of Revenue administrative officer. Attorney Travis Noble will use the administrative hearing in an attempt to prevent the suspension of your driver’s license and to elicit information from the arresting officer that could be used in your criminal DWI case.


The breath test machine used to test blood alcohol content in Missouri. To produce evidence that is admissible in court, Breathalyzer machines must be properly maintained and operated.


Acronym for blood alcohol content.

Blood alcohol content

The amount of alcohol in a 100 milliliter (ml) volume of blood, expressed as a percentage. In Missouri, you can be charged with DWI if you have a blood alcohol content of .08 percent or more. Holders of commercial driver’s licenses can be charged with DWI for a blood alcohol content of .04 percent or more. Those under 21 can be charged with DWI for a blood alcohol content of .02 percent or more.

Blood test

One of the tests used by police to determine blood alcohol content. Blood tests are frequently used in DWI injury and vehicular homicide cases. To be admissible as evidence, blood must be properly drawn and stored and the chain of possession documented.

Breath test

A means of measuring blood alcohol content. There are two types of breath testing methods in Missouri. Police officers use portable breath testing machines in the field. Results from portable machines are used only for the purposes of determining whether there is probable cause to believe a driver is intoxicated. Readings from portable breath test machines lack reliability and cannot be used in court to prove intoxication. The second type of breath test machine is the Breathalyzer. This machine can produce more accurate results that are admissible as evidence, provided that the machine has been properly maintained and the tests administered properly.


Missouri Department of Revenue. The Driver License Bureau of this agency is responsible for issuing and revoking driver’s licenses in Missouri.


Driving under the influence. This is the legal term for impaired driving used in Illinois and most states. In common speech, it is often used interchangeably with DWI.

DUI Drug

Driving under the influence of drugs. Also called DUID and DWI Drug. In Missouri, you can be convicted of DWI if the state can show that legal or illegal drugs impaired your driving.


Driving while impaired. This is the legal term for the criminal drunk driving charge in Missouri. In common speech, it is often used interchangeably with DUI.

Field sobriety tests

Three standard tests established by the National Highway Traffic Safety Administration to help police officers determine whether there is reason to believe that a driver is impaired. They are the horizontal gaze nystagmus, one-leg stand, and walk and turn. If it can be shown that the officer failed to administer the tests properly, the DWI charge could be overcome.

Horizontal gaze nystagmus

One of the three standard field sobriety tests. The driver must keep the head still while following a flashlight with the eyes. The horizontal gaze nystagmus test requires skill to administer, and there can be nonalcohol reasons for an inability to pass this test.

Ignition interlock device (IID)

This is a device similar to a portable breath test device used by police. If you are convicted of DWI in Missouri, you will have to pay to have this device installed in your vehicle for at least six months. To start your vehicle, you have to blow into a tube. If the IID indicates that you have a blood alcohol content of .025 percent or more, your vehicle will not start.

Implied consent

Under this law, any driver in Missouri whom the police suspect of impaired driving must consent to a blood alcohol test. Refusing such a test can result in the revocation of your driver’s license.

Mouth alcohol

Any residual alcohol in a person’s mouth. It could come from the person’s esophagus, throat, sinuses, stomach, chewing gum or other sources. The presence of mouth alcohol can produce false breath test results.

One-leg stand

One of the three standard field sobriety tests. The test requires the driver to stand on one leg continually for 30 seconds. If the driver cannot do this, it could provide the officer with reason to believe that the driver is impaired.

National College for DUI Defense

Associated with Harvard University, this is the nation’s leading school for training DWI defense attorneys. Travis Noble is a graduate of this institution.

Observation period

This is the 15-minute period prior to the administration of a Breathalyzer test. If the subject is not granted this observation period, is seen to be belching or burping, or there are other irregularities, any resulting breath tests could be inadmissible in court.

Petition for Review (PFR)

A legal tool that a lawyer can use to stop the automatic suspension of a driver’s license. It stays a suspension pending the outcome of the criminal DWI case. If you consented to a BAC test, you have 15 days from the date of the traffic stop to file a PFR. If you refused to blow or submit to a blood or urine test, you have 30 days from the date of the refusal to file a PFR.

Probable cause

Simply stated, this refers to the belief of a police officer (obtained by observation, field sobriety tests or a BAC test) that a driver was impaired at the time of the stop. If it can be shown that the officer did not have probable cause to believe that the driver was impaired, the DWI charge could be dismissed or reduced to a nonalcohol driving offense or result in a not guilty verdict.

Reasonable suspicion

The legal basis by which a police officer can stop a driver. There are 20 standard clues to nighttime drunk driving that can justify a stop. If the officer cannot confirm that he or she had reasonable suspicion of impaired driving under cross-examination, the DWI charge could be dismissed or reduced to a nonalcohol driving offense or result in a not guilty verdict.

Restricted license

After a DWI conviction, it may be possible to obtain restricted driving privileges that enable you to drive for certain purposes. After the restricted period has elapsed, you may be able to apply for reinstatement of your driver’s license.

SIS probation

SIS stands for suspended imposition of sentence. In this type of outcome, you plead guilty to the DWI charge. You are placed on probation for a set period of time, must attend alcohol or drug counseling sessions, and get an ignition interlock installed in your vehicle. If you comply with the terms of your probation and are not charged with any other crimes, no DWI conviction is entered in your record.

Sobriety checkpoint

This is a blanket traffic stop in which every vehicle is stopped and drivers observed for signs of intoxication. Sobriety checkpoints must be properly set up and administered.

SR-22 certificate

If you are convicted of DWI, the judge may require you to prove that you have insurance coverage. Your insurance company will issue the SR-22 certificate for this purpose.

Urine test

One of the chemical tests that police can use to establish impairment. It is often used to corroborate breath test results or when police suspect impairment by drugs.

Walk and turn

One of the three standard field sobriety tests. It consists of two parts. First, the officer will instruct the driver how to perform the test. If the driver starts the test too soon or cannot keep his or her balance during instruction, it could provide the officer with reason to believe that the driver is impaired. In the second part, the driver must take nine heel-to-toe steps in a straight line, turn 180 degrees, and take nine heel-to-toe steps in a straight line. If the driver staggers, stumbles, veers off course or fails to follow instructions, it could provide the officer with reason to believe the driver is impaired.

Wet reckless

Refers to the reduction of a DWI charge to a reckless driving charge. This can happen when a prosecutor does not have sufficient evidence to prove a DWI or when police have made procedural mistakes that do not allow the introduction of certain evidence. A wet reckless enables a driver to avoid a DWI conviction and driver’s license suspension, though it can result in a fine and driver’s license points.

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