Police Observation During a DWI Arrest in Missouri

A DUI Checkpoint is based on the observation period. Usually, this period begins as soon as the police officer or other witness sees or even hears you.

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Kimberly J. Benjamin, Founder & Managing Attorney

July 27. 2022.

What Happens During a Missouri DWI Arrest?


Driving after drug or alcohol consumption can result in charges for driving while intoxicated (DWI), regardless of how far you had to drive or whether your designated driver left you behind. If there is reasonable suspicion of drunk driving, such as driving erratically, law enforcement officers will pull you over for probable cause.

 A police officer may take the driver to jail for failing a portable breath test or a field sobriety test. For them to be admissible in court as evidence, field sobriety tests must be conducted according to strict procedures. 

Lawyers in Kansas City may be able to help you if you have been arrested for DWI in Missouri.

DWI Police Observation Period in Missouri


In Missouri, blood and breath tests require at least 15 minutes of observation of the DWI subject before taking the breath test. An observation period ensures that the breath sample is not contaminated by anything you do. During this time, no smoking or oral intake of any material is allowed; if the suspect vomits, the 15-minute observation period starts over. 

Mouth alcohol can cause artificially inflated test results. If mouth alcohol is present, it is believed to disappear after 15 minutes, producing accurate BAC results. During the BAC test, the officer must constantly observe the driver. They must look for anything that can cause or raise mouth alcohol, such as burping, belching, or vomiting. Unless this is done correctly, the State may be unable to demonstrate that the testing process was properly conducted, leading to suppression of the results and removal of any foundation for DWI charges.

During the observation period, DWI suspects have the right to remain silent and have their attorney present. Contact reputable lawyers in Grandview, MO, for advice and representation if you have been detained for driving under the influence. By developing a solid attorney-client relationship with a reputable law office, you may be able to avoid a DWI conviction and a driver’s license suspension.


Mouth Alcohol in Breath Tests

Breathalyzer test results can be affected by mouth alcohol, even if there are trace amounts of alcohol in the mouth. It occurs when a small amount of alcohol remains in the mouth or throat, contaminating your breath as it passes through the breathalyzer. DUI breath tests will detect this alcohol before it is absorbed into the bloodstream, producing a falsely high BAC reading, which can lead to innocent people being charged with DUI.

Several products contain alcohol, including:

  • Cold medicines

  • Mouthwashes

  • Breath sprays

  • Chewing tobacco

In rare DWI cases, elevated blood alcohol levels can also be caused by medical conditions such as gastroesophageal reflux disease (GERD) or acid reflux. Usually, this occurs after drinking alcohol.

Mouth Alcohol as a DWI Defense


Kansas City DWI lawyers can raise a mouth alcohol defense when:

  • A law enforcement officer did not wait the full 15 minutes before conducting the test or waived the 15-minute observation period altogether.

  • During those 15 minutes, the officer didn’t continuously watch the driver.

  • GERD or other digestive issues may have caused mouth alcohol to regurgitate, and there is proof of this condition.


Repercussions of DWI Conviction in Missouri

A DWI is a criminal offense in Missouri. If the DWI arrest leads to a conviction, the offender will face significant penalties that vary depending on the BAC level and the number of prior DWI convictions. These include:

  • License revocations

  • Fines

  • Jail time

  • Higher insurance rates

A blood alcohol level of .08 or more is considered legally drunk for non-commercial drivers over 21 years of age. Those driving commercial vehicles, including school buses, are legally intoxicated if they have a blood alcohol level of at least .04 percent. A driver under 21 with a blood alcohol level of .02 or higher is considered legally drunk and will suffer particularly harsh penalties under Missouri’s zero-tolerance laws.

Highly-trained criminal defense attorneys in Kansas City, MO, may be able to help you avoid the consequences of driving under the influence.

How a DWI Lawyer in Missouri Can Help


A DWI arrest lawyer in Missouri can help with various legal issues, including a warrant, traffic tickets, and other criminal charges. They can advise and represent you at the DWI checkpoint, police station, and the trial, where they can present evidence of your innocence. The Missouri DWI & Criminal Law Center represents clients in the following circuit court locations:

  • Charles County

  • Jefferson County

  • Louis County

Depending on the details of your DWI arrest, your attorney may be able to negotiate a hardship-driving privilege for you. This would allow you to enjoy restricted driving privileges, reducing the negative impact a DWI conviction can have on your life.

Contact us today to schedule a free consultation with a Missouri DWI lawyer.

Frequently Asked Questions About Missouri DWI Arrests


What Is the Difference Between a DWI Arrest and a DUI?

Under Missouri law, there is no difference between DWI (driving while intoxicated) and DUI (driving under the influence). These interchangeable terms refer to a driver legally impaired by alcohol or drugs, with a BAC above .08 or higher (.04 for commercial drivers).

What Happens if You Refuse a Field Sobriety Test in Missouri?

While field sobriety tests are voluntary in Missouri, those who refuse to take them may be arrested. A driver’s license is not automatically suspended if the driver refuses the field sobriety test.

Can You Refuse a Chemical Test After a DWI Arrest in Missouri?

Missouri law requires you to submit to a chemical test after being arrested for DWI. Despite Missouri’s “implied consent” law, you may refuse to take an alcohol or drug test. Nonetheless, if you refuse, you run the risk of losing your Missouri driving privilege for a year, also known as a chemical revocation.

Can a DWI Be Dismissed in Missouri?

In Missouri, a person may be able to get their DWI charges dismissed if they can prove the following:

  • They were not actually driving at the time of the incident.

  • The arresting police officers did not have probable cause to stop you for DWI suspicion.

  • The arresting officers deviated from the standardized field sobriety test and incorrectly administered the breath or chemical tests.

In other circumstances, they may be able to have their charges reduced to one with more lenient penalties.

If you are facing DWI charges in Missouri, it is essential to speak with an experienced Missouri DWI Lawyer as soon as possible.

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