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Iowa breath tests for OWI can be inaccurate

A drunk driving conviction in Iowa can seriously affect a person's life. In addition to fines and possible jail time, the defendant will face driver's license revocation and may be required to have an ignition interlock device installed on the person's vehicle. In a felony drunk driving or vehicular homicide case, a conviction can result in years in state prison.

This is why it's important not to take the accuracy of OWI breath tests for granted. In fact, breath testing machines often yield inaccurate results. Successfully challenging these results in court can mean the difference between a conviction and a dismissal of the charges.

The breath testing machine used by Iowa law enforcement is called the DataMaster. Its results can be challenged if the officer administering the test wasn't properly certified, if the machine was not calibrated correctly or if proper instructions were not given to the defendant. Even if the machine was working properly and the test was administered according to protocol, differences in body temperature and metabolic rate between individuals can skew the results.

Most OWI prosecutions in Iowa rely heavily on breath test evidence. This evidence can be challenged in court by cross-examining the officer who administered the test or by presenting expert testimony as to the DataMaster's limitations.

Iowa defense lawyers J. Dean Keegan and Thomas D.S. Farnsworth have extensive experience challenging DataMaster test results in court. Mr. Keegan is well-versed on the science of measuring blood alcohol content through breath tests. A former prosecuting intern, Mr. Farnsworth has seen firsthand how prosecutors prepare and present breath test evidence in court. For more information on how we challenge Iowa breath test results in court, please see our defenses to OWI/DUI web page.

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IOWA Association for justice IOWA state bar association NACDL 1958 national association of criminal defense lawyers american association for justice board certified specialist DUI defense law the iowa state bar association


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J. Dean Keegan, Eric D. Tindal & Andrea Mason Attorneys At Law
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