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How Reliable are Breath Test Machines?

Posted by Unknown | Nov 05, 2019 | 0 Comments

In 2018 there were a total of 29,267 DUI charges filed in Washington State Courts. Out of those charges, 11,073  resulted in findings of guilt. In many DUI cases, the results of a breath test machine is the primary evidence that the courts rely upon in finding people guilty. Throughout Washington, police departments make regular use of the Dräger Alcotest 9510 for breath testing. The Drager makes use of both infrared light and a fuel cell sensor in order to determine the amount of alcohol present in a sample of someone's breath. These machines are billed as highly accurate and scientific machines - ones that can be relied on to get convictions, but a recent expose  by the New York Times casts a huge amount of doubt on this assertion. 

In 2009 Washington implemented use of the Drager 9510 statewide, even though a scientific review by the Washington State Patrol itself suggested that the devices were “not yet ready for implementation.” In 2015, a preliminary scientific report was generated in conjunction with a court case. That report was retracted after the authors began facing pressure from Drager, a giant corporation, to withdraw, but copies are still available. That report found that “The Alcotest 9510 is not a sophisticated scientific measurement instrument. As mentioned in the technical background, it consists of a mere two sensors capable of detecting the presence of ethanol or confounding substances. Further, the apparatus depends in large part on calibration with external standards to scale the measurements produced by the instruments to measured breath alcohol concentration numbers,” and “does not adhere to even basic standards of measurement.” According to the New York Times expose, one of the disable safeguards was the measuring of breath temperatures: "Breath samples that are above 93.2 degrees — as most are — can trigger inaccurately high results." 

This problem is not exclusive to just Washington, or this specific breath machine. It's turning into a national problem. Between Massachusetts and New Jersey alone 42,000 DUI convictions are currently at risk because of invalidated test results. 

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