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Breath testing challenges in DUI cases – Virginia DUI defense

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Breath testing challenges in DUI cases - Virginia DUI defense

Breath testing challenges in DUI cases – Virginia DUI defense

Breath testing in DUI needs a critical review, says Virginia DUI lawyer

Breath testing is the preferred method of alcohol testing by police officers in Virginia DWI cases. As a Virginia DUI lawyer, I know that a full-court press needs to be pursued against breath testing results in such cases. Breath testing is fallible both with the equipment and material used, and with the actions of the breath testing operator and the person blowing into the machine.

Virginia DUI attorney on the importance of knowing the DFS Operator Instructional Manual

A Virginia DUI defense lawyer needs to obtain and know the Intox EC/IR II Breath Test Operator Instructional Manual by the Department of Forensic Science (DFS Manual), found here. For starters, the Virginia form certificate of blood alcohol analysis for breath testing, includes an attestation clause for the breath test operator that says in pertinent part that “the test was conducted… in accordance with the methods approved by the” DFS. That means the breath test operator must himself or herself know the manual, and that the manual is permissible for use in cross examining the operator.

Virginia DUI lawyer on cross-examining the test operator on the twenty-minute observation period

The DFS Manual requires a twenty-minute observation period by the breath test operator, and is addressed at pages 12, 15, 16, 18, and 22 of the Manual. This observation period is essential to reduce the risk of testing mouth alcohol versus alcohol in the lungs. Emphasizing the necessity of the twenty-minute observation period, the Manual states: “Experiments have shown that residual mouth alcohol will be eliminated by normal body processes well within 20

Fairfax DUI lawyer says breath testing results should be inadmissible if the breath test operator does not have the suspect open his or her mouth

Breath testing results should not be admissible at a Virginia DUI trial if the testing operator did not have the suspect open his or her mouth at least twenty minutes before blowing into the machine. Some operators will admit that they do not recall whether they had the suspect open their mouth. The Manual commands: “The Department of Forensic Science operator and instrument protocols, along with the Intox EC/IR II have several safeguards in place to prevent an inaccurate analysis and to ensure a valid test.Visual inspection of the mouth: Inspecting the mouth prior to conducting the observation period ensures that no foreign object(s) are within the mouth. If found, the foreign object(s) should be removed and a 20 minute observation period observed.”

Virginia DUI lawyer on determining when the first sample was given

Analyzing compliance with the twenty-minute rule involves not only looking at the “Time Sample Taken” line on the Certificate of Analysis, but also by obtaining and reviewing the applicable DFS Breath Alcohol Analysis Log, which often will list an earlier time of the suspect’s first blow into the machine, at the SUBJ line. The 20-minute observation period must have commenced prior to the time of that first blow.

Some additional items to attack in DUI breath testing cases

A Virginia DUI lawyer should also look out for the dry gas standard (a control mechanism) check. Deviation between the dry gas standard value (listed as Dry Gas Std on the DFS Breath Alcohol Analysis Log) and the Intox EC/IR II’s check (listed as CHK) of the same might mean that the breath test result is too high. For instance, on page one of this DFS Breath Alcohol Analysis Log  for the second test subject, the dry gas standard target value is 0.099 but the check thereof is elevated at 0.100, which means that 0.001 must be subtracted from the lowest machine result of 0.119. Although that deviation may seem minor by itself, it can become more significant when also incorporating the DFS-admitted margin of uncertainty together with the Intox EC/IR II’s mis-assumption of a 34 degree Celsius mouth temperature.

Virginia DUI lawyer Jonathan L. Katz pursues your best defense against DWI, drugged driving, intoxicated/ drunk driving and impaired driving charges. To discuss your case with Jon Katz, please call his staff at 703-383-1100 to discuss your case.