Studies show breath tests are not always accurate

Breath test devices may not always give accurate BAC results, which could result in an erroneous DUI conviction.

Although having a few drinks when going out to dinner is not illegal in Maryland, driving while intoxicated is against the law. People who are suspected of drinking and driving may be pulled over by a law enforcement officer and asked to submit to a roadside breath test. Officers in Maryland and across the U.S. use these small machines to determine whether a driver's blood alcohol content level is above the legal limit. If the breath test device emits a reading that shows the driver's BAC is at 0.08 percent or higher, he or she may be charged with a DUI.

The problem lies in the fact that not all breath test devices produce accurate and reliable readings. Multiple studies have found that there is a significant margin of error when it comes to comparing readings obtained from breath test devices to the results received from actual blood tests. It is within these variances that an innocent person may be arrested, charged and even convicted of drinking and driving.

Blood tests vs. breath tests

Breath analyzing devices work by evaluating how much alcohol is found in the driver's breath sample. Blood tests, on the other hand, measure the amount of alcohol in the blood directly. Researchers from the State University of New York at Potsdam found, however, that at least one in four drivers had a higher breath test reading than their actual blood test results. In some cases, the results varied by at least 15 percent.

Factors that contribute to breath test device inaccuracy

Rather than simply measure the amount of alcohol contained in a breath sample, there are other factors that can alter a breath test reading. Researchers concluded that these factors include the following:

  • The relative humidity and temperature of the air.
  • Whether the officer is using the device correctly.
  • Cigarette smoke, pollution, gasoline fumes or other substances in the air.
  • Any residual food, drink or vomit contained in the driver's mouth.
  • Electrical interference from cellphones or officer radio devices.

In addition to these factors, breath test devices that have not been calibrated and/or maintained on a regular basis may not give reliable results.

Where to turn in your time of need

A DUI conviction can affect many areas of your life, including your career, finances and family. Not only do you run the risk of losing your driver's license and ability to travel around town, but you may find it hard to find a job in certain industries or even apply for a financial loan. A criminal law attorney in Maryland may be able to answer your questions when it comes to dealing with a DUI.