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Iowa Breath Test Machines Can Give Inaccurate Results

In a recent post we discussed the weaknesses of Iowa's standard field sobriety tests as evidence of intoxication. Field sobriety tests are generally used as an initial indicator of intoxication; if the arresting officer concludes the tests show a driver is drunk, the next step is usually a breath test. Blood tests are considered more accurate than breath tests but they are used less often because they are considered more invasive.

Breath test machines are often generically referred to as Breathalyzers, which is actually a brand name for just one of many machines in use across the country. Iowa uses a machine called the DataMaster. This device is not infallible; in fact the DataMaster has been shown to be prone to erroneous results.

Like most breath test machines in use today, the DataMaster uses infrared light to measure the alcohol present in a driver's exhaled breath. Different levels of alcohol will result in different spectrums of light, and the DataMaster converts this spectroscopic information into a measure of blood alcohol content.

There are a number of ways to challenge breath test results in court. Some studies have shown that breath test results can differ by as much as 15 percent from blood test results, which are considered a more accurate measure of a person's actual blood alcohol content. Design flaws, improper calibration of the machine, differing results based on the machine's temperature or the driver's body temperature and different levels of hematocrit in the bloodstream are all potential grounds to attack the results of a DataMaster test.

A drunk driving arrest in Iowa is a serious matter with potentially severe consequences. An experienced OWI defense attorney who understands the limitations of breath test evidence can provide invaluable help in fighting the charges.

Source: Findlaw, "BAC Test FAQs," accessed March 20, 2016

Categories
  • The Iowa State Bar Association
  • DUI Defense Law
  • NACDL
  • AAJ
  • Iowa Association of Justice

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  • J. Dean Keegan
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  • J. Dean Keegan J. Dean Keegan

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    Decades of Award-Winning Legal Service J. Dean Keegan was born and raised in Waterloo, Iowa. After high school, Dean served ...
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  • Eric D. Tindal Eric D. Tindal

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    Highly Rated Criminal Defense in Iowa City Eric D. Tindal, attorney at Keegan, Tindal & Mason, graduated from the University ...
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  • Andrea D. Mason Andrea D. Mason

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    Experienced Criminal Defense in the Iowa and Illinois Quad Cities Andrea D. Mason practices in the areas of white collar ...
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  • Operating While Intoxicated Record Expunged

    Johnson OWCR106890. Attorney Dean Keegan's client received an Operating While Intoxicated, a serious misdemeanor. After reviewing the videos, Mr. Keegan filed a Motion to Suppress arguing the officer denied his client's right to make a phone call. The State declined to present testimony at the hearing and the Motion to Suppress was granted, making the client eligible for a deferred judgment. Mr. Keegan's client will have her record expunged and be able to obtain a license after 90 days instead of 180.

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    Johnson County No. OWCR039210, Iowa City, Iowa. Attorney J. Dean Keegan conducted a three-day long suppression hearing which presented the first challenge to the "Drug Recognition Protocols" used in Iowa.

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    Cedar Rapids, Linn County, Iowa. An employee of a Cedar Rapids business accused of embezzling six million dollars was not charged criminally after the County Attorney agreed to abide by an agreement negotiated by Attorneys J. Dean Keegan and Jerald Kinnamon in which the accused would pay two million dollars to the company.

  • Vehicular Homicide Charge Dismissed

    Johnson County No. FECR058630- Iowa City, Iowa. Attorneys J. Dean Keegan and Jerald W. Kinnamon successfully challenged the withdrawal of blood from a Defendant without his permission after a rollover accident in which a passenger in the vehicle was killed.

  • Vehicular Homicide Charge Dismissed

    Muscatine County No. FECR03718 - Muscatine, Iowa. If convicted of the vehicular homicide while intoxicated, as alleged in this case, the Defendant would have faced the possibility of a 25-year prison sentence, 17 years of which would have to be served before he would be eligible for parole. Following the depositions of the investigating officer and consultation with an accident reconstruction expert, Attorneys J. Dean Keegan and Jerry Kinnamon negotiated the dismissal of Vehicular Homicide as part of a plea

  • OWI Charge Dismissed

    Johnson County No. OWCR083001 - Iowa City, Iowa. Attorney J. Dean Keegan alleged that the Defendant's rights to contact a lawyer or family member may have been violated after his arrest. He requested video of the breath test from the arresting officer to support his allegation. When the officer failed to produce the video evidence in response written requests, a subpoena, and a Motion to Compel, the State conceded the issue and dismissed the offense.

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    Johnson County No. OWCR077717- Iowa City, Iowa. Acquittal at jury trial of a defendant accused of Operating While Intoxicated who refused a breath alcohol test. Tried by Attorney J, Dean Keegan.

  • OWI Case Overturned

    State v. Hornik, Segura, et. al.Iowa City, Johnson County, Iowa. When the state of Iowa established that the Datamaster breath testing machine could be used to test subjects being investigated for OWI, it failed to establish a protocol for its proper use. Attorney J. Dean Keegan, in conjunction with the Johnson County Public Defender's Office, mounted a challenge to the use of the machine based on the lack of uniform instructions for its operation.

  • Zero Tolerance Driver's License Revocation Zero Tolerance Driver's License Revocation Overt

    Iowa Dept. of Inspection and Appeals Docket No. 08DOTOW3937. Attorney J. Dean Keegan successfully challenged a "Zero Tolerance" license revocation on the basis that the officer had failed to allow the driver to contact a family member or attorney for legal advice before submitting to the test.

  • OWI 2nd Offense Charge Dismissed

    Muscatine County No. OWCR040280 - Muscatine, Iowa. After Attorney Dean Keegan scheduled the deposition of the State's expert witness in this case, he learned that the breath test was inappropriately administered by the arresting officer. The State dismissed the offense outright and agreed that the breath test result should be inadmissible so the Defendant would not face the proposed one-year administrative revocation of her driver's license.

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