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The Draeger AlcoTest 9510-Here’s What You Need to Know

Posted Wednesday, September 26, 2018 by Andrew Charles Huff

Washington rolled out their brand new breath-alcohol machine approximately five years ago with mixed reviews. The Draeger-AlcoTest 9510, a German-manufactured device analyzes a person’s breath for police to estimate the alcohol level in a person’s blood. Based on our DUI laws, anyone who blows a .08 or above within two hours of driving is presumed to be driving under the influence. However, a prosecutor must prove beyond a reasonable doubt this issue and recent developments in DUI defense strategies have created reason to doubt the instrument and its results.

How does the Draeger 9510 work?

The Draeger 9510 runs on software that the state has yet to properly validate because the manufacturer has not been forthcoming with this information. The software controls the data when the instrument is used to collect and test a breath alcohol sample. Every quarter second, sensors check and record flow rate, volume, breath alcohol level and time to ensure the minimum criteria for a breath sample is achieved.Washington DUI law requires that the instrument only test “end expiratory air” – the last portion of air exhaled by the driver into the Draeger. The technical manual further clarifies that the minimum criteria for a valid sample requires at least 1.5 liters of breath exhaled and that the individual blow for at least five seconds. Blowing should only stop after the arresting officer notices the quarter-second readings of breath results are starting to plateau, meaning they’re not increasing at a rate greater than .04/second.

The instrument plots a graph of the breath result data for the officer and displays it on the built-in screen. When the graph starts to plateau, and the officer sees that at least five seconds have past and at least 1.5 liters of breath volume has been blown into the instrument, they have collected their first valid sample.

Valid vs. non-valid sample

A valid sample creates a graph that is always rising. Any dip in results followed by a sharp rise indicates the presence of “mouth alcohol” or other interference which makes the result invalid.

Mouth alcohol refers to alcohol not coming from a person’s breath, but something else in the surrounding or ambient air or a contaminant in the driver’s mouth, like food particles, or other items that negate the validity of the test according to the Draeger technical manual. Graphs that decrease followed by a sudden increase indicate an invalid test, and the jury would have plenty of reason to doubt the breath result based on this data.

Call my office to discuss this issue and more at 206-729-3477.

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