Unreliable Alcohol Breath Tests in DWI/DUI Court Cases

The Washington State Supreme Court found that the state broke its own rules for maintaining alcohol breath-testing machines and has ruled unanimously that alcohol breath tests in cases of alleged drunken or impaired driving aren’t admissible in court if they haven’t been properly calibrated to reduce inaccurate readings. This, of course, protects innocent drivers from being convicted on the basis of incorrect breath test readings.

Experts have argued that the machine’s thermometers, which must be absolutely accurate for accurate readings, weren’t properly maintained, were inaccurate, and therefore led to false readings. To reduce this problem, the state adopted regulations requiring periodic verification of the machines’ thermometers. However, the state hasn’t followed its own rules for many years, if ever. One prosecutor complained that “the rules have become our own worst enemy.”

However, a new state law now specifically prohibits alcohol breath test readings from being barred from court just because they might be invalid or incorrect. The law makes it easier to get questionable, possibly inaccurate, breath-test readings admitted into court.

Apparently, prosecutors want to increase their conviction rates, regardless of the guilt or innocence of the citizens suspected of driving while under the influence of alcohol.


  • O’Hagen, Maureen. State broke breath-test rules. Seattle Times, July 2, 2004; Fox Bowman Duarte Notes That Washington Supreme Court Prohibits Use of Controversial DUI Breath Test Results. Business Wire, July 1, 2004; New law supersedes Supreme Court ruling on breath tests. Seattle Post Intelligencer, July 1, 2004.

Filed Under: Driving Breathalyzer