cedar rapids / iowa city criminal defense

What does breath test refusal mean and how can it be used against me? 

by David Cmelik

I see social media posts from my colleagues who universally advise their clients to refuse to comply with the preliminary breath test (PBT) as well as the more reliable and accepted Datamaster DMT breath test.

This is both a personal and scientific decision. We all know from sixth grade science class that alcohol is absorbed more quickly than it dissipates. In other words, four shots of vodka pounded ten minutes before a traffic stop will nearly instantly spike blood alcohol over the prohibited .08 grams per 100 L blood or more and take on average at least four hours to fully metabolize. That’s because the conventional wisdom is that it takes the body one hour to metabolize .02 grams of alcohol per 210 L breath or 100 L of blood.

In contrast, if it has truly been four or five hours since a test subject had “a couple”—literally two and not a minimized three, four, or five— twelve ounce beers, it is a very personal decision to decide whether to provide a breath sample, but chances are better that BAC will be lower than the example above involving four pounded shots.

In Iowa, this is made more complicated because, pursuant to Iowa Code § 321J.6, once an officer has reasonable grounds to believe that a motorist is impaired, he or she may request a preliminary breath test. A refusal is grounds to immediately invoke implied consent and require the motorist to either consent or refuse to provide a breath sample for the Datamaster DMT. Most officers will arrest for OWI (DUI) a test subject who refuses a PBT. Query whether an officer will heed a BAC less than .08 grams per 210 L breath—or simply rationalize an arrest as impairment by something other than alcohol. Moreover, a Datamaster DMT refusal may be used as evidence of guilt in Iowa—something law enforcement officers need not tell test subjects.

So it adds injury to an Iowa OWI (DUI) arrest to say, “you shouldn’t have blown” or “don’t blow” without information on how much the defendant had to drink in the hours leading up to the administration of a PBT or Datamaster DMT. I depends on the situation. 

If you or a loved one has been arrested for OWI (DUI) in the State of Iowa, Cedar Rapids, Iowa City, Waterloo, Linn, Johnson, Black Hawk, Benton, Jones, or other Iowa counties, please contact David A. Cmelik Law PLC. Get legally informed. But remember that a blog is not legal advice and sending information to an attorney over the Internet does not establish an attorney-client relationship.


It's too much of a pat answer to say "don't blow" or "you should have refused." The decision to provide a breath sample for both the preliminary breath test and, later, the Datamaster DMT test, is both a deeply personal and a scientific decision that depends on consumption of alcohol over time, science, as well as your goals over a period of months if not years. Moreover, it's "Monday morning quarterbacking" to speculate as to whether a test refusal is better than the likely result. If you or a loved on has been charged with OWI (DUI) in Cedar Rapids, Iowa City, Waterloo, Vinton, Anamosa, Linn, Johnson, Black Hawk, Benton, Jones, or other counties, contact David A. Cmelik Law PLC to become an informed legal consumer today. 

Partner with David A. Cmelik Law PLC today to expose any potential defects in the prosecution and put them to work for you in your Iowa OWI (DUI) defense. 

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