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Researchers Silenced after Expressing Doubt about Breath Test Instrument’s Reliability

May 15th, 2018 Breath Testing OWI Researchers Silenced after Expressing Doubt about Breath Test Instrument’s Reliability

Modern breath test instruments used in the investigation and prosecution of alleged drunk drivers are specialized computers that, like all computers, run on a program.  The instructions contained in these programs, called source code, tell the breath test instrument what to do and what not to do.

In the State of Washington, a defense attorney hired two software engineers to review the source code from the breath test instrument used in that state, called an Alcotest 9510, which is made by Draeger. The two software engineers prepared a report critical of Drager’s Alcotest 9510, and when they disseminated this report, they were slapped with an injunction which precluded them from making their opinion’s public.  Draeger claims they sought the injunction not to silence the researchers but instead  to protect their intellectual property.

The Alcotest 9510 uses both infrared and fuel cell technology to separately measure the arrested driver’s breath alcohol. The results of this duplicate test should be within a small margin of error. If they are not then the test will be rejected.  According to the report prepared by the engineers, the Draeger breath test can return a false high result that push a person over the legal limit.  One reason cited for this is the lack of adjustment for breath temperature.

In the context of drunk driving, breath temperature is important because high body temperatures will force more alcohol from the blood into the breath.  This means the reported breath alcohol amount will not accurately reflect the actual amount of blood alcohol. Even small differences in temperature can be important because just a single degree over the average breath temperature (34 degrees centigrade) can artificially increase a corresponding breath test result by as much as six percent.  In some cases a six percent difference can be the difference between guilty and not guilty.

According to an article that ran in ZDNet:

The Washington State Patrol said the police department tested and approved the instrument that best fit their business needs and believe the device can produce accurate results without the breath temperature sensor.

In other words, the ostensibly defective source code used in the Washington breath testing instrument is “good enough for government work.”

This is not unlike the 2006 decision by the Michigan State Police when they ordered the DataMaster DMT to replace the aging breath test instruments then in use.  The new device had virtually unlimited data storage capabilities and a breath volume and alcohol level graphic display.  The Michigan State Police made the decision to order the DMT without either function.  Trouble is, both the historical data as well as the breath test graph from a single arrested person could show that an allegedly illegal breath test result is actually inaccurate or unreliable.  Again, this could mean the difference between guilty and not guilty. But, like Washington, Michigan decided that the lower featured DMT fit their business needs, and is good enough for the government!