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  • Writer's pictureDavid A. Cmelik Law PLC

2 kinds of Iowa DUI breath tests

The DUI (OWI) breath test machines that we commonly call “breathalyzers” are actually divided into two categories in Iowa: preliminary breath test, or, PBT, machines and desktop evidentiary breath test machines, or, DMTs, in Iowa.

Think of the PBT machines as portable but also preliminary, or, first. By law, PBTs are not admissible to prove guilt on the issue of intoxication in front of the jury. They are, however, admissible to prove that the officer had the initial, or, preliminary, “reasonable grounds” to trigger “implied consent” and request a more evidentiary, desktop test called the Datamaster DMT back at the stationhouse. Think “Desktop” for DMT and “Portable” or “Preliminary” for PBT to keep them straight in your mind. A PBT is one of a battery of field sobriety tests. There are 14 portable PBT devices certified for use by law enforcement in the State of Iowa manufactured by five different companies. They are handheld and carried by officers in their patrol cars. They use disposable tubes, or, straws.

Usually, a police officer will advise a test subject that they have no obligation to blow into a PBT device and that it is "not admissible in court." This is not technically correct. It is not admissible in a jury trial on the issue of intoxication but prosecutors may offer the PBT test result as a response to a pretrial motion challenging the reasonable grounds to believe someone is operating under the influence. Reasonable grounds are required to request that the test subject and defendant provide a breath sample for ethanol testing using the evidentiary Datamaster DMT, or, desktop, test.

There is just one evidentiary, desktop machine approved for use in Iowa and it is the Datamaster DMT. Most of the Datamaster DMT machines in Iowa were put into use over a decade ago. The desktop DMT machine test results are typically recorded “memory tests” that are used as evidence in a criminal prosecution for Operating While Intoxicated, or, OWI—commonly called DUI or DWI in other states. There is a maintenance record for each DMT maintained by the Department of Public Safety by serial number.

By Iowa law, if timely requested, correctly advised, and properly administered, the Datamaster DMT breath test result is presumed by the trial court to be the blood alcohol content of the Defendant and test subject in a drunk driving prosecution. In Iowa, Iowa Code § 321J.1 defines intoxication as .08 g ethanol per 210 L breath, 100 mL blood, or 67 mL urine. A result at or above that limit is considered to be presumptively intoxicated.

Searching for the best DUI lawyers? We want to be on your list of candidates for representation. If you or a loved one have been arrested for Operating While Intoxicated in violation of Iowa Code § 321J.2, contact us for a free initial consultation.


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