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Evaluating the accuracy of Colorado breath test devices

Although breath test devices may be used to arrest a motorist for drinking and driving, studies show that their results may be unreliable.

When a Colorado motorist is pulled over on suspicion of drinking and driving, law enforcement officers may ask the driver to blow into a breath test device. These machines are supposed to tell officers how much alcohol the driver has been drinking by measuring their blood alcohol content level. According to Colorado law that went into effect in January of 2014, people who refuse to take a breath test may be considered persistent drunk drivers and could lose their driver’s licenses for one year. Yet, multiple studies show that the results of breath test devices are not reliable, and may inflate the driver’s actual BAC level. In some cases, the erroneous readings obtained from a breath test device may lead to the wrongful arrest and drunk driving conviction of an innocent person.

A study reported by the State University of New York at Potsdam found that breath test results can vary by 15 percent when compared to a blood alcohol content level obtained from a blood test. At least 23 percent of people tested using a breath test device will have inflated BAC results. These extreme differences can have a major effect on distinguishing whether a driver is intoxicated.

Unreliable breath test results

Why are the results from a breath test device different from BAC readings obtained from a blood test? There are a number of factors that affect the reliability and accuracy of breath test readings. Not only are the results dependent on the officer’s ability to use the breath test device properly, but the machine must also be calibrated on a regular basis in order to avoid bad results.

Substances found in a driver’s mouth, such as certain foods, drinks, mouth wash, vomit or blood, may enhance a blood alcohol content level reading. If the subject has diabetes or is on a strict diet plan, they may have chemicals in their saliva, which can alter the BAC level as well.

Other factors that influence breath test results include:

  • Tobacco smoke or other pollutants in the air
  • Interference from a cellphone or police radio
  • The temperature and humidity of the air
  • Fumes from cleaners, paint or paint thinner
  • Engaging in strenuous exercise

One study involved a man who had not had any alcohol to drink. After spray painting a room for 20 minutes while wearing a protective mask, the man had a breath test reading of .075 percent. The results of the blood test, however, showed that the man had no alcohol in his system.

Legal assistance may be necessary

It can be difficult to face DUI charges on your own. A wrongful DUI conviction can have devastating results. A criminal defense attorney in Colorado may be able to provide essential legal counsel during your hard time.

Keywords: DUI, drunk driving, breath test, arrest