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  • Breath Tests in Virginia

  • Are Law Enforcement Breath Tests Accurate?

    Many law enforcement agencies across the country use breath test devices as part of their procedure to identify whether or not a driver is driving while intoxicated. People who have been pulled over on suspicion of drunk driving in Virginia may have been asked to submit to a breath test, which usually involves the driver blowing into a tube. The device, according to the Century Council, then analyzes the amount of alcohol that is present in the breath sample and converts it into a blood alcohol concentration level. The problem lies in the fact that many of these breath test devices are unreliable, and produce false DUI results which could affect an innocent person's life forever.

    Blood Alcohol Content vs. Breath Alcohol Content 

    Although a breath test device estimates a person's blood alcohol content level by reading the amount of alcohol present in his or her breath, blood alcohol levels and breath alcohol levels differ in many ways. According to Motorists.org, blood alcohol content can be accurately determined by measuring a blood sample.

    Researchers performed a study comparing the BAC levels calculated from a blood sample and a breath sample. The results showed a 50 percent discrepancy between the blood sample and the BAC obtained from the breath test device. In other words, a breath test BAC reading of 0.1 percent, which is above Virginia's legal limit of 0.08 percent, may inaccurately represent a BAC level of anywhere between 0.05 percent, which is not considered intoxicated, and 0.15 percent. This significant margin of error is enough to charge an innocent person of a DUI.

    Factors Affecting Breath Alcohol Content

    According to the State University of New York at Potsdam, many breath test machines analyze the amount of ethyl alcohol that is contained in a person's breath. While ethyl alcohol is found in alcoholic beverages, it is also found in a number of other substances, which can alter the accuracy of a breath test reading. The university reports that the following can lead to false results:

    • Eating certain types of bread products.
    • Inhaling paint, paint thinner or gasoline fumes.
    • Interference from cell phones and police radios.
    • The presence of dirt, tobacco smoke or moisture in the air.
    • The presence of vomit or blood in the mouth.

    One study found that BAC results changed drastically after people were subjected to strenuous physical activity, including running up the stairs. Another found a significant change in blood alcohol levels after people, who were wearing a protective mask, spent 20 minutes in a spray painted room.

    When to Seek Legal Counsel

    If you were charged with a DUI after submitting to a breath test, or you feel as though you have been wrongfully charged with driving under the influence of alcohol, you may want to consider seeking legal counsel from an established attorney.