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Personal Breathalyzers: Do They Work?


Today, more and more people are purchasing breathalyzers for their personal use. These popular devices are specifically designed to calculate the percentage of alcohol present in an individual’s bloodstream, providing them with their current blood alcohol content, or BAC, which indicates whether or not they are over the legal driving limit. However, personal breathalyzers are steeped in controversy, because an inaccurate device may result in a DUI. We consulted Barry Bobbitt, a Dallas based criminal lawyer to find more information about the accuracy of personal breathalyzers and how they hold up against the law.

Personal Breathalyzers - Do They Work

Factors That Affect the Accuracy of a Personal Breathalyzer

Many people assume personal breathalyzers work, but do they accurately reflect the user’s BAC? The answer to this question largely depends on the make and model of the device, the type of sensor that is used, and the maintenance and calibration intervals of the device.

The Importance of the Right Sensor

Many professional grade personal breathalyzers utilize sensors with fuel cell technology that calculate the electrical charge created by the body’s electrochemical reaction to alcohol. Although fuel sensors give fewer false readings than other types of sensors, they require frequent calibration. If they are not calibrated properly, readings may not be as accurate as believed.

Semi-conductor sensors, on the other hand, measure a person’s BAC by calculating the amount of alcohol in a person’s breath from their lungs. Depending on the materials that are used, these types of personal breathalyzers come in a wide range of accuracy levels. Some varieties have the same level of accuracy as breathalyzers that use fuel cell technology. Others, however, provide considerably less accurate readings. In fact, some of these breathalyzers can be off by more than .02 percent.

A Warning from Police

In addition to the potential accuracy problems of these devices, police officials have also voiced their concern regarding drivers receiving a false sense of confidence in their driving abilities due to using breathalyzers. In a recent interview with Colorado Springs’ KKTV, Colorado Springs Police Sgt. Glenn Thomas, said, “They are not accurate, they are not reliable.”

The only way to receive a truly accurate BAC measurement is through the use of a blood test. Despite this, personal breathalyzers are becoming increasingly popular and providing drivers with the wrong information. According to Sgt. Thomas, “They say they took a portable test before they left the bar and they passed it, but then they show impairment and their blood alcohol content is at a different level then what they said.”

This means that if a police officer believes a person is impaired, he or she can still be arrested for DUI even if their personal breathalyzer indicated that their BAC was under the legal limit. Therefore, a test performed with a personal breathalyzer may not prevent a DUI arrest.

Bottom Line

In the end, the accuracy of a personal breathalyzer depends upon the type of device that is used. However, it is safe to say that they do not work as expected across the board. If someone chooses to trust a personal breathalyzer, they should purchase a quality device that provides the best accuracy possible. Ultimately, a person should only choose a breathalyzer that has an approximate accuracy of +-.005. Thankfully, there are models available that provide this reasonably high level of accuracy, but they must still be properly calibrated and maintained, which requires additional costs. Regardless of the model chosen, someone can still be charged with a DUI even if their personal breathalyzer shows that they are not impaired.

About the author:

The Dallas based criminal law firm, Bobbitt Law, has fought for the rights of 80,000 satisfied clients over the past decade. For more legal insight and articles, connect with them on Facebook.

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