The breath test devices used by Missouri law enforcement officers to determine whether a person is intoxicated, may yield inaccurate results.

When a Missouri law enforcement officer pulls over a person on suspicion of driving under the influence of alcohol, he or she may ask the driver to submit to a breath test. Officers use these devices to determine whether people are driving with a blood alcohol content level that is over the legal limit of 0.08 percent. Yet a myriad of credible studies show that these devices have a high rate of inaccuracy and may give erroneous readings. In some cases, an innocent person may receive a DUI because of an inaccurate breath test reading.

How do breath test devices work?

Rather than measure the driver's blood alcohol content level directly by taking a blood sample, a breath test device determines how much alcohol is present in the driver's breath sample. The driver is asked to blow into a tube that is connected to the device, and once the breath alcohol content level is calculated, it converts the number to a blood alcohol content level. Studies show that these converted BAC levels may not be a fair representation of the actual blood alcohol content level. Furthermore, breath test devices pick up more than simply alcohol on a person's breath, which can sway the results.

Factors that affect a breath test reading

A study conducted at the State University of New York at Potsdam found that breath test devices are sensitive to methyl alcohol structures as well as ethyl alcohol structures. Although these two groups are extremely similar in design, methyl groups can be found in normal human saliva, as well as several other substances. If a person has recently rinsed with mouthwash, eaten food, had something to drink or smoked a cigarette, it will also alter the BAC reading. Researchers reported the following factors that can affect a breath test reading as well:

  • The amount of humidity in the air
  • Interference from cellphones and police radios
  • Whether the officer is using the device properly
  • Whether the device has been properly calibrated and maintained

One study found that a man's blood alcohol content reading on a breath test device was elevated after he had painted a room for an hour. The subject was wearing a mask the entire time he was painting. However, he had inhaled a large concentration of paint fumes which ultimately increased his BAC level percentage.

When to contact an attorney

If you have been charged with a DUI, you may want to seek legal counsel from an attorney in Missouri. People who are convicted of a DUI may have trouble finding employment in certain industries, lose their driver's license, pay hefty fines and even spend time in jail. A DUI lawyer will listen to the details surrounding your situation and help to explore your options.

Keywords: breath, field, test, DUI, drunk driving, arrest

Travis Noble is a graduate of the National College for DUI Defense at Harvard University, and he lectures at seminars nationwide on DWI/DUI topics. He is the lawyer whom other lawyers consult to defend their DWI clients. Most importantly, he has a track record of successfully defending some of the toughest DWI cases in Missouri and beyond.

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