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Accuracy of Virginia breath testing questioned by Fairfax DUI lawyer

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Aug 11, 2020 Accuracy of Virginia breath testing questioned by Fairfax DUI lawyer

Accuracy of Virginia breath testing questioned by Fairfax DUI lawyer- Photo of beer glass

Accuracy of Virginia breath testing questioned by Fairfax DUI lawyer

Accuracy of breathalyzer testing is far from what the Virginia Department of Forensic Science claims, says Fairfax DWI lawyer

Accuracy of breathalyzer testing is what I always am ready to attack as a Virginia DUI lawyer. Today’s blog entry is all the more important, to counter the Virginia Department of Forensic Science’s (DFS’s) unsupportable FAQ claim that “breath tests are very accurate.” Let us count the ways that this DFS claim is inaccurate, as addressed here and below:

Blood testing accuracy is superior to testing by breathalyzer / Intox EC/IR II

Virginia DUI law — which starts with Virginia Code § 18.2-266 — gives police the sole option whether to agree to an arrestee’s request to submit to blood testing rather than breath testing. An arrestee might prefer blood testing for such reasons as hearing that blood testing is more accurate than breath testing for blood alcohol content (BAC), if the Virginia DWI arrestee suffers from GERD / acid reflux, if the suspect has been burping or frequently burps or vomits, or if the arrestee has a weak breath that may not enable him or her to provide a sufficient breath sample to obtain a BAC reading in the Intox EC/IR II machine, which is the sole breath testing machine approved by the Virginia Code for DUI cases.

Furthermore, blood testing rather than breath testing is the sole BAC analysis basis that allows for independent review of the test, in that Virginia law enables the defendant to obtain a court order to submit a portion of the remaining blood sample to a private lab of the DUI defendant’s choosing, for an independent BAC analysis of the blood. With breath testing, there is no retained breath sample to send to an independent laboratory. Greater accuracy of blood over breath testing is clear.

Why is blood testing not used more often than breath testing in Virginia DUI arrests? Blood testing costs more money and time for the arrest and trial dates

If blood testing gives more accuracy than breath testing for DUI investigations, why is blood testing not used more often than breath testing in Virginia DWI prosecutions? Money and time investment is the only reason I can think of. Breath testing is quicker than blood testing, and can use as few as one witness at trial when the sole witness on the scene is the reporting police officer and if that police officer is the same person who administers the breath testing.

Blood testing, on the other hand, requires at least three witnesses: A police officer who observes the defendant’s behavior on the scene, the person who draws the DUI suspect’s blood, and a forensic toxicologist from the DFS. Where the DFS toxicologist who signs off on the certificate of analysis reporting the blood alcohol level has relied on another person or persons at the DFS to actually examine the blood, the Sixth Amendment’s Confrontation Clause calls for the presence at trial of the DFS staffmember who examined the blood. Therefore, Virginia’s favoring breath testing over blood testing is not about accuracy but instead aboutmoney and time expense.

Fairfax DUI blood trial dockets  are backlogged, which is likely another reason that police would be disinclined to grant a DWI arrestee’s choice of a blood test over breath test

As a Fairfax DUI lawyer, I know that at the first trial date for a DWI case, the written Fairfax County General District Court procedures manual allows either the defense or prosecution to obtain a new trial date, if the case does not reach a negotiated settlement on the first trial date and if both parties do not jointly choose to proceed to trial on the first trial date. If a Fairfax DUI case involves a blood draw, it is common for the new trial date to be set months later, apparently in recognition that the DFS forensic toxicolgists also need to be spending time in other courts and at their laboratory, and in recognition that’s such trials can take longer than breath test DWI trials. As stated above, Virginia favoring breath testing over blood testing is not about accuracy.

Virginia DUI conviction penalties are brutal, and the state DWI law should not exalt breath testing thresholds for obtaining convictions and mandatory minimum sentencing

The science of breathalyzer testing is subject to too much error — some of which is addressed above — to make breath BAC testing the centerpiece of obtaining a Virginia DUI conviction. Unfortunately, the Virginia Code creates a rebuttable presumption that a 0.08 BAC result creates a rebuttable presumption that “the accused was under the influence of alcohol intoxicants at the time of the alleged offense.” Va. Code § 18.2-269. This rebuttable presumption deifies science, when scientific testing is subject to error that we learn about along the way, including discoveries with inaccuracy in fingerprint analysis and revelations of inaccuracy issues so severe in the nation’s capital that for a long time the metropolitan police there were not using the Intox EC/IR II nor other breathalyzer machines. Such deification of breathalyzer machines in Virginia DUI cases is the epitome of anti-science, in that true scientists demand full rigor in developing and assessing the accuracy of forensic testing.

Following are a few additional reasons why breath testing accuracy if unreliable for Virginia DUI cases: Even the most accurate BAC testing only checks the current blood alcohol level, and not the blood alcohol level at the time of driving. The blood alcohol level of a DWI arrestee could well have been significantly lower at the time of driving than at the time of testing, because first alcohol absorbs into the bloodstream (sending the BAC higher than at the time of first consuming alcohol), then the blood alcohol level plateaus, then the blood alcohol dissipates, and a question is whether the blood alcohol level might subsequently rise again. Yap v. Virginia recognizes this truism in stating that whether a person is in violation of the Virginia DUI law depends on the defendant’s BAC level at the time of driving, not at the time of breath or blood testing. The subsequent Wimbish v. Virinia case threw a wrench in that Yap engine by doing an about face in ruling that for prosecutions for alleged blood alcohol levels of 0.15 or higher, we are to look at the BAC at the time of testing.

On top of that, the Virginia DFS itself provides for a margin of uncertainty of +/- 0.004 margin of uncertainty for BAC readings under 0.15 and +/- 0.008 for BAC readings at or over 0.15. For more information about accuracy problems with breathalyzer testing for Virginia DUI cases, see here.

Fairfax DUI lawyer Jonathan L. Katz pursues your best defense against felony and misdemeanor prosecutions. Call 703-383-1100 for a free in-person consultation with Jon Katz about your court-pending DWI or criminal case. 

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