Breathalyzer machines can be alarmingly unreliable, investigation shows

by Daniel Payne · Nov 4th, 2019 4:53 pm
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Last Updated Nov 20th, 2019 at 10:11 am

Breathalyzers — machines used to measure someone’s blood-alcohol content, or BAC — are popularly held to be an ironclad way to determine if someone is too drunk to drive. Millions of drivers are arrested for DUI each year based on the results given by breath tests. Yet a recent investigation has shown that the tests can be unreliable.

The New York Times conducted an extensive review of thousands of pages of court records, contracts, and other documents, as well as spoke with more than 100 experts and legal advisors. The paper said it uncovered a “nationwide problem” related to the alcohol devices, which “generate skewed results with alarming frequency.”

In one instance, the paper discovered, a police consultant discovered that a department’s machines were giving results 20 to 40 percent higher than it should have been. In another, a machine produced two substantially different results from the same subject yet did not notify the user of the discrepancy.

One examination of a company’s alcohol-testing machine determined that it “[did] not adhere to even basic standards of measurement.”