SCOTUS’s Birchfield decision misses the gross inaccuracy of breath testing in DWI cases

Fairfax/Northern Virginia DWI lawyer, pursuing the best defense since 1991

Oct 23, 2016 SCOTUS’s Birchfield decision misses the gross inaccuracy of breath testing in DWI cases

The United States Supreme Court does no good when its opinions provides more dicta than needed. That is abundantly clear in the Court’s recent Birchfield driving while intoxicated/driving under the influence (DWI/DUI) case. Birchfield v. N. Dakota136 S.Ct. 2160 (2016).

Criminally penalizing refusal to submit to breath and blood testing is the issue in Birchfield. Consequently, Birchfield wastes six pages of dicta sanctifying breath alcohol testing, which should never be sanctified, because breath testing is fraught with inaccuracy, unreliability, and insufficient correlation to sobriety levels.

The most harmful of the dicta by Birchfield’s majority — none of whom ever prosecuted nor defended a criminal case at the trial court level — parrots back unreliable conclusions about the accuracy of breath testing in DWI cases, particularly in asserting that breathalyzer machines  “are generally regarded [by whom?] as very reliable because the federal standards [issued by a pro-DWI prosecution-biased federal government] require that the devices produce accurate and reproducible test results at a variety of BAC levels, from the very low to the very high.”

For starters, the Intox EC/IR II breathlyzer machine, which is used in Virginia (which state makes it a crime to drive with a 0.08 or higher blood or breath alcohol level, which hardly correlates with intoxication), assumes a 34 degree celsius mouth temperature, does not check for nor adjust for higher mouth temperatures (even though a large percentage of people have mouth temperatures of 35 and 36 degrees celsius), and results in a falsely high reading the higher one’s mouth temperature exceeds 34 degrees celsius.

The Intox EC/IRII is less accurate if using an inaccurate dry gas standard control mechanism, or if the standard’s target value is lower than the checked dry gas standard value. The Virginia DFS admits margins of uncertainty in breathalyzer testing starting at a .004 plus/minus uncertainty margin, and a .007 uncertainty level for BAC readings starting at 0.15.

Moreover, breathalyzer machines are unable to account between the dichotomy of breath alcohol levels at the time of driving versus at the time of testing, where breath alcohol levels can rise, fall or stay the same during that interval, depending on whether the alcohol is at the time absorbing into the bloodstream, dissipating out of the bloodstream, or staying at a steady level during the two intervals. To experience this absorption phenomenon itself, drink four bottles of beer, and then go for a vigorous run for at least five minutes; you will feel the effects of the alcohol much more quickly than if you had remained sedentary.

Additionally, the breathalyzer does not know whether the person administering the test has assured a twenty minute observation period to reduce the chance that the breathalyzer machine is testing for mouth alcohol (which is not supposed to happen) versus checking deep lung air, which is supposed to take place. Consequently, the breathalyzer machine does not account, either, for its inaccuracy with burping or belching (where police threats of a refusal charge for repeated burping or belching can lead the suspect not to report burping or belching), nor with acid reflux/GERD sufferers, who can unknowingly have contents from their esophagus enter their mouth, leading mouth alcohol to be checked by the breathalyzer machine.


Consequently, breath alcohol testing is far inferior to blood testing, which is less favored than breath testing by law enforcement, because of the extra time and money expense involved not only in administering blood testing, but also in getting three witnesses to trial for blood testing cases (the arresting police officer, blood drawing person, and blood analyst) versus for breath alcohol testing (which can involve as few as one prosecution witness). Moreover, because Birchfield confirms that a blood draw (but not a breath test) is a search under the Fourth Amendment, police will all the more favor breath testing over blood testing in DWI cases.

The next time the Supreme Court reviews a DWI case, it will be important to enlighten the justices on how inaccurate are breathalyzer machines.


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