PinUnder Minnesota’s implied consent law, a motorist suspected of DWI/DUI does not have the right to refuse a breath test to determine intoxication as is the case with a blood or urine test where a warrant is required. However, there are several requirements necessary to ensure breath test validity.

First, it is important to understand the difference between a preliminary roadside breath test and the test at the police station. The roadside test is simply to determine if a stopped motorist may be driving drunk or otherwise chemically impaired. Confirmatory tests are conducted at the police station—often with more sophisticated machinery—and these results determine whether a subject will face prosecution.

Adherence to the observation period

Before a motorist takes a breath test, the police officer is supposed to observe the subject for 15-20 minutes to ensure that abdominal alcohol is not introduced into the mouth or that the subject doesn’t introduce anything into his/her mouth. Because of the higher concentration of abdominal alcohol, belching, burping, or vomiting could increase one’s mouth alcohol and give a skewed result. This observation period ensures that mouth alcohol dissipates and no new sources are introduced.

In many cases, this observation period doesn’t involve actual observation. However, the burden of proof that the motorist was not adequately observed falls on the defendant’s shoulders to prove that the officer failed to ensure the validity of the breath test.

For example, in one case a police officer wrote in his report that while observing the subject, the subject burped but did not belch, yet he failed to differentiate the two. The officer also failed to conduct another observation period to ensure mouth alcohol dissipation. At the implied consent hearing, the judge dismissed the case because of inadequate scientific safeguards.

Proper use of breathalyzer equipment

A police stop is based on an officer’s observation of a motorist’s driving and his/her behavior following the stop. These observations are not scientific, so the use of breath testing machines helps support (or, in some cases, refute) the officer’s claims that a subject was driving drunk.

In Minnesota, the DataMaster DMT is the go-to device for DWI evidentiary breath testing after many legal challenges surfaced about the previous device, the Intoxilyzer 5000EN. Even though the DataMaster DMT is considered far more reliable, the machine is far from infallible, and the way in which it is used and maintained significantly impact its accuracy.

A police officer must be trained and properly certified to administer breath tests. A good defense attorney will always investigate the officer’s credentials to ensure they are valid and current. The attorney will also ensure that the test was conducted in accordance with departmental policy and per the machine’s operation manual. If testing procedures are not followed, then the test can be argued as inaccurate, unreliable, and invalid.

Similarly, a breath machine must be properly maintained and calibrated, and a good DWI/DUI attorney will request the department’s records to ensure such is the case.

Beware of stomach alcohol

A DWI/DUI breath test measures mouth alcohol left over from alcohol consumption. There is also stomach alcohol which is much stronger. The officer administering the breath test must observe the subject 15-20 minutes before administering the test to ensure the subject doesn’t burp, belch, vomit, or place anything into his/her mouth that may skew the results.

How physical illness can compromise breath test accuracy

The DataMaster DMT used infrared spectroscopy to measure a subject’s blood alcohol content, and this technology is based on certain assumption such as normal body temperature, for example. Thus, if a subject has a fever—and the police officer is unaware—the breath machine may provide skewed results. Therefore, a common cold, flu, pneumonia, or other illness may have a significant impact on one’s DWI case.

Thus, proper administration of a breath test is critical for a successful DWI/DUI prosecution. Retaining the services of a qualified and experienced attorney are crucial to ensure that the evidence admitted in court is both legitimate and valid.