A breath test result at or above Missouri's legal limit can look like powerful evidence in a DWI case. But a number on a breath-testing machine does not automatically settle the case.
Missouri has rules governing evidential breath testing, including requirements involving approved methods, testing equipment, maintenance, and the qualifications of people administering chemical tests. Whether those requirements were satisfied can become an important issue when defending a DWI charge.
If you were arrested for DWI in Kansas City after taking a breath test, the circumstances surrounding that test deserve careful review.
Missouri law allows chemical testing of a driver's breath, blood, saliva, or urine under circumstances authorized by the state's DWI laws.
For most adult drivers, a blood alcohol concentration of .08 percent or higher can trigger administrative driver's license consequences. The same breath test may also become significant evidence in a criminal DWI prosecution.
These are related but distinct proceedings.
A Kansas City driver may therefore face both:
The breath test result can be important in both proceedings, which is one reason it should not simply be accepted without examining how the test was obtained.
Our Kansas City DWI defense attorney can review the breath test and the other evidence surrounding a Missouri DWI arrest.
Yes.
A breath test is scientific evidence produced through a testing process. That process depends on multiple factors, including the equipment, its maintenance, the test operator, and compliance with Missouri's applicable procedures.
A challenge may focus on whether the state can establish the necessary foundation for using the breath test result.
Missouri courts have addressed compliance with Department of Health and Senior Services requirements when determining whether breath test evidence is admissible.
That means a Kansas City DWI defense can involve much more than arguing about whether a driver "felt drunk."
The records behind the breath test can matter.
Maintenance records can be important when reviewing a breath test.
Missouri's regulatory system includes requirements governing evidential breath analyzers and maintenance checks. The state may need to establish compliance with applicable requirements when laying the foundation for a breath result.
A DWI attorney may examine records associated with the specific instrument used in a Kansas City case.
Questions may include:
A machine's printed result does not tell you any of these things.
Reviewing the underlying records can provide a much fuller picture of whether the result should be relied upon.
Missouri law requires chemical analysis under the state's implied consent provisions to be performed according to approved methods and by appropriately qualified personnel.
For breath testing, the operator's permit and compliance with the approved testing procedure may therefore be relevant.
A Kansas City DWI investigation should include identifying who administered the test and whether that person was properly authorized to operate the instrument at the time.
The defense may also compare the operator's report with other evidence, including police reports and available video.
Even when an officer has extensive DWI experience, the testing procedure still matters.
Breath testing is not simply a matter of turning on a machine and asking someone to blow into it.
Missouri has established procedures for evidential breath analysis. Depending on the device and circumstances, records associated with the test can show whether required steps were documented.
An attorney reviewing a Kansas City DWI case may look for issues involving:
A departure from a procedure does not automatically mean that every breath result will be excluded. The legal significance depends on what happened, which requirement is involved, and how Missouri law applies.
Breath-testing instruments are intended to evaluate alcohol in breath, but alcohol remaining in or around the mouth can create concerns in some circumstances.
Potential sources of residual mouth alcohol can include recently consumed alcohol or regurgitation.
This is one reason pre-test procedures can matter.
If something occurred shortly before the breath test that could affect the reliability of the sample, the circumstances should be investigated rather than ignored.
Body-camera or station video can sometimes be useful because it may show what happened during the period before a Kansas City driver's breath sample was collected.
A breath result should be evaluated in the context of the entire DWI investigation.
Police may also rely on evidence such as:
Suppose an officer describes severe impairment but video shows the Kansas City driver communicating clearly and performing substantially differently from the description in the report.
That does not automatically invalidate a breath result, but inconsistencies can matter when evaluating the state's overall case.
Likewise, the timing of the breath test can be relevant. A test performed later does not literally measure the driver's breath alcohol concentration at the exact moment the vehicle was being driven.
Not necessarily.
Missouri law distinguishes portable breath testing used in the field from evidential chemical breath testing.
A preliminary breath test may be used by an officer during a roadside investigation. Missouri law places specific limits on how preliminary breath test results may be used, and these devices are not treated identically to evidential breath analyzers used to establish blood or breath alcohol concentration.
This distinction can be confusing after a Kansas City DWI arrest because a driver may have been asked to provide more than one breath sample.
It is important to identify which test was given, where it occurred, and how the prosecution intends to use it.
Alcohol does not instantly enter the bloodstream when a person drinks it.
Depending on factors such as when alcohol was consumed, absorption can continue after a person stops driving.
This can create a timing issue in some DWI cases.
For example, a Kansas City driver may be stopped and then tested later at a police station. If alcohol was still being absorbed during that period, the breath alcohol concentration measured later may not necessarily be identical to the concentration at the time of driving.
Whether this issue is significant depends on the individual facts and available evidence.
An attorney may review the drinking timeline, traffic-stop timeline, testing time, statements, and other evidence when evaluating whether alcohol absorption is relevant.
The effect depends on the case.
A successful challenge to breath evidence does not necessarily mean the entire DWI case automatically disappears.
The prosecution may have other evidence it intends to use, including officer observations, driving behavior, field sobriety tests, statements, and video.
However, breath test evidence can be an important part of the state's case.
Questions concerning admissibility or reliability can therefore significantly affect both the criminal DWI proceedings and, depending on the circumstances, a related driver's license matter.
Every Kansas City DWI case should be evaluated based on its own evidence rather than assumptions about what normally happens.
A thorough DWI investigation can involve much more than the police report.
Depending on what exists in the case, potentially relevant material may include:
These records can help reconstruct the sequence from the initial traffic stop through the breath test.
They may also reveal inconsistencies that are difficult to identify by looking at the reported BAC number alone.
For someone arrested in Kansas City, preserving and reviewing this evidence early can be an important part of preparing a DWI defense.
Yes. A reported BAC above .08 does not eliminate the need to examine the evidence.
The defense may need to consider the legality of the traffic stop, probable cause for the arrest, the breath-testing procedure, maintenance documentation, operator qualifications, video evidence, and other circumstances.
There may also be separate driver's license deadlines that require prompt attention.
Denise Kirby's practice focuses on DWI defense, including breath and chemical testing issues, and she has practiced in the Kansas City area for decades.
The objective is not to assume that a test is wrong simply because the result is unfavorable. It is to determine whether the evidence was lawfully obtained, properly administered, and supported by the records required in a Missouri DWI case.
A breathalyzer result can be important evidence, but it should not be viewed in isolation. The testing device, maintenance records, operator qualifications, procedures, video evidence, and timing of the test can all deserve review after a Kansas City DWI arrest.
If you are dealing with a DWI charge involving a breathalyzer test in Kansas City, our attorney is here to help. Call us today or connect with us online to schedule a consultation.
