Research shows breath tests are not always accurate

People who take a roadside breath test may be wrongfully charged with a DUI due to device inaccuracies.

Whether people are enjoying drinks while sitting by the pool or having a few cocktails with dinner, it is crucial that they think before climbing behind the wheel of a vehicle. People who decide to drink and drive run the risk of getting pulled over by law enforcement and may be asked to submit to a roadside breath test. Although these devices are used by officers across Minnesota and throughout the nation, studies show that the reliability of breath test machines is poor. In fact, research from the State University of New York at Potsdam shows that 23 percent of people who take a roadside breath test will have an inflated reading, which could lead to a DUI charge.

Unreliable results

The problem with hand-held breath test machines is that there are several factors that can influence the results. The device is designed to detect the presence of ethanol alcohol in a driver's breath sample, and then covert that number to a blood alcohol level. Instead of simply measuring the amount of ethanol alcohol, however, the machine also picks up different compounds in the driver's mouth, such as residual blood, vomit or food.

In addition to these compounds, there are other factors that can influence breath test results. These include the following:

  • Substances in the environment, such as pollution, cigarette smoke or gasoline fumes.
  • Poor maintenance and/or improper use of the breath test machine.
  • Electrical interference from cellphones, officer radios or other electrical devices.

The temperature and humidity of the air can also have an effect on breath test readings.

Blood alcohol level vs breath alcohol level

While the breath test machine is designed to convert the amount of alcohol found in the breath to a blood alcohol level, the results do not always match up. A study conducted by LaBianca, Simpson, Thompson et.al. found a variance of up to 50 percent when comparing blood alcohol content levels taken from a breath test device to the BAC obtained from a blood test. This means that a person with a BAC level of 0.05 percent may have a breath test reading of 0.1 percent, which could lead to a DUI conviction.

Upholding your rights in court

A DUI can have long-term consequences on your life. Not only will a conviction on your record make it difficult to apply for financial assistance, but you may have trouble finding a job or obtaining a professional license. A DUI attorney in Minnesota may be able to look at the details surrounding the specific incident and offer options that could improve the outcome of your case.