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Can I challenge the results of my BAC in a DUI?

The California Supreme Court recently decided a San Diego DUI case that will have a far-reaching impact on DUI law. In People v. Vangelder, 2013, the court addressed whether DUI trials could limit the type of evidence presented by experts to challenge the reliability and scientific accuracy of breath testing machines used to calculate someone's blood alcohol concentration (BAC).

The device at issue in Vangelder, the Intoximeter EC/IR breath-testing machine, was designed to analyze and sample the BAC contained in the deep lung air, alveolar breath, as required under of Title 17, Section 1219.3 of the California Code of Regulations.

The defendant argued that breath testing machines were not reliable in testing the BAC because some alcohol present in bronchial vessels and mucus membranes located in the upper airways absorbs into the breath before it finally reaches the alveolar sacs in the deep areas of the lungs. Therefore, the breath testing machine was not measuring the BAC from the alveolar breath.

There are other factors that affect the reliability of the machines to accurately measure the BAC – the pattern of breathing (speed and depth of inhalation), body and breath temperature, and hematocrit level (ratio of red blood cells, to total blood volume).

For the most part, the Court rejected this argument and held that defendants can challenge the reliability of a particular machine, not argue that breath testing machines are always unreliable. That is, the defense can argue that a particular breath machine was not calibrated correctly or was not functioning properly.

If you were arrested or charged with DUI, contact Kern Law, APC, today and speak with me personally about your case.