Problematic DUI Detection in Utah

June 12, 2011 (Press-News.org) The Utah Commission on Criminal and Juvenile Justice reported 15,285 arrests for driving under the influence in 2010. Utah police use a machine called the CMI Intoxilyzer 8000 to take a breath alcohol content reading (commonly known as a breathalyzer test) of a driver suspected of driving under the influence of alcohol. This breath sample is analyzed and converted into a blood alcohol concentration. Breathalyzer test machines were developed in the 1950s as an alternative to what many believed was an overly-invasive blood test for BAC.

Over the years, lawmakers and law enforcement personnel began to accept BrAC readings from breathalyzers as accurate estimates of people's BACs, despite being indirect tests. Test designers thought that the machines would measure the alveolar or "deep-lung" air of an exhaled breath. Such air is in equilibrium with the blood, leading to the assumption that the amount of alcohol in that air is the same as the amount in a person's bloodstream.

Inherently Inaccurate Readings From the Equipment

Despite how heavily police and the courts rely on the results of breathalyzer tests, forensic scientists and toxicologists are still unclear about the exact science behind breathalyzer tests. Several well-documented problems with the Intoxilyzer 5000 and Intoxilyzer 8000 have led to calls for police to stop using them.

According to the 2007 study by Stefan Rose, M.D. and Kenneth G. Furton, Ph.D. entitled "Variables Affecting the Accuracy and Precision of Breath Alcohol Instruments Including the Intozilyzer 5000," the machines routinely register ethanol, the type of alcohol found in alcoholic beverages, in breath samples when there is actually a different chemical present. Additionally, the machines often give elevated readings due to a number of biological variables and problems with the machines themselves. The study notes the margin of error on the reading can be as high as 27 percent. Another interesting fact, based upon the different biological factors and predetermined calculation factors, the Intoxilyzer is accurate, regarding the subjects actual BAC, eleven percent (11%) of the time.

How Utah's "Single Breath" Testing Procedure is Even More Flawed

The majority of the states that do rely on the Intoxilyzer 5000 or Intoxilyzer 8000 require police to administer two tests on the machine to ensure consistency in the reading and avoid mouth alcohol false readings. In Utah, however, police only take one reading of a suspect's BrAC with the Intoxilyzer. Without replicate testing, this brings into question the accuracy and reliability of that breath test.

Furthermore, Utah police often demand that the person taking the breath test keep blowing for up to 10 seconds, despite the fact that 80 percent of the reading is taken in the first three seconds of the test. The extra air from the extended time a suspect blows into the machine forces a greater number of molecules into the test chamber, making it seems as if there were more alcohol molecules in the suspect's breath sample and skewing the BAC reading higher than it would be were the test administered differently. Police refer to this phenomenon as "the harder you blow, the higher you go".

If you are stopped by the Utah police on suspicion of driving under the influence of alcohol, do not hesitate to consult an experienced criminal defense attorney as soon as possible.

Article provided by Greg S. Law, PLLC
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