• 314.645.4400
  • Free Consultation
  • Call 24/7


Breathalyzer | BAC Breath Test

A driver’s Blood Alcohol Content (BAC) is used to determine his or her level of impairment. In Missouri, there are two BAC standards used to charge someone with DWI. The standard used is 0.08% for drivers 21 years of age or older and 0.02% for individuals under the age of 21.

If the driver provided a chemical sample, the driver or his or her attorney must request an administrative hearing with the Department of Revenue. The administrative hearing will initially be heard by a Department of Revenue hearing officer. If the hearing officer decides to uphold the license suspension, the driver may file a Petition for Trial De Novo in state court. It will then be up to the judge if the license suspension will be upheld or overturned.

Missouri Breath Testing

The most common chemical test requested of a driver in a Missouri DWI case is a chemical breath test. While Missouri’s Implied Consent Law allows a police officer to request a blood or urine sample upon reasonable grounds to believe the driver was operating a motor vehicle in an intoxicated or drugged condition, they rarely do. However, in cases involving motor vehicle accidents or where a driver may be unconscious, blood draws are much more common.

Breath Test as Evidence

To convict an individual for DWI in Missouri, the prosecution must prove beyond a reasonable doubt that the driver was operating a motor vehicle in an intoxicated or drugged condition. One critical piece of evidence that prosecutors love to have is a breath test result showing that a driver was driving a vehicle with a BAC above the legal limit. Although breath test machines are hardly reliable, BAC results provide the prosecution with some form of objective evidence.

If a driver refused to submit to a chemical test, the prosecution’s case is based largely on the arresting officer’s opinion, the defendant’s statements, field sobriety test results, and possible a portable breath test result.

Defending a DWI Breath Test Case

If you submitted to a chemical test, the St. Louis DWI lawyers of Henderson & Waterkotte, P.C. can challenge the test results, the officer’s opinion, and the method in which the field sobriety tests were conducted. In a DWI case, there are specific standards in which a police officer must adhere to when conducting a DWI investigation and making an arrest. There is a lot of room for error. Most police officers do not perform every phase of the investigation and arrest properly. At Henderson & Waterkotte, P.C., our DWI defense lawyers understand the breath test machines, know what mistakes are commonly made by police officers, and will investigate all the facts and circumstances pertaining to your arrest to obtain the best possible result for you.

Contact a St. Louis DWI Lawyer Today

At Henderson & Waterkotte, P.C., we handle cases ranging from a first-time DWI offense to felony DWI cases throughout Missouri and Illinois. Our experienced DWI lawyers understand this complex area of law, and know what steps to take to protect your rights. We will work tirelessly to obtain the best possible result for you. Contact us today for a free consultation. We are available 24 hours a day, 7 days a week.