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Reviewing the accuracy of breath test devices

On Behalf of | Jan 17, 2017 | DUI/DWI

In New Jersey, and in most other states across the nation, law enforcement officers use roadside breath test devices to determine whether a driver is operating a vehicle while intoxicated. If the breath test device measures the driver’s blood alcohol content level at 0.08 percent or above, he or she may be arrested and charged with drinking and driving. However, multiple studies show that breath test device results are not always accurate and could show inflated readings in some situations. This could lead to a false arrest and erroneous DUI charge.

A study conducted by the State University of New York at Potsdam measured the accuracy of these devices. Researchers found that in addition to measuring the presence of alcohol in a breath sample, the machines picked up traces of other substances that could cause an inaccurate BAC reading. In fact, the following substances and factors have been shown to affect breath test readings. These include:

  •          Blood, vomit or residual food or drink in the subject’s mouth.
  •          Cigarette smoke.
  •          Relative humidity and temperature of the air.
  •          Electrical interference coming from law enforcement officers’ radios, cellphones and other electronic devices.
  •          Pollution and dirt in the air.
  •          Certain medication.

In addition to these factors, people who have been exposed to certain chemicals, including paint and cleaner fumes, may have elevated BAC readings. Machines must be calibrated properly and used correctly by law enforcement officers in order to give accurate readings.

According to the study, breath test readings can have up to a 15 percent variance when compared to readings taken from actual blood samples. This means that one in four drivers that take a breath test may be potentially mistakenly charged with a DUI.