Accuracy of Breathalyzers called into question

Law enforcement in most states, including Tennessee, rely on breath testing equipment to assist in determining whether a driver they have pulled over for a DUI. The machines appear to be the perfect device to quickly determine blood alcohol content (BAC) of a driver, providing scientific evidence to present in court and obtain a conviction.

Breathalyzers are sophisticated technology. They analyze the alcohol vapor in your breath and through complex calculation; they display a number that is supposed to be your BAC. However, that number is only an approximation; an accurate BAC measurement can only be done using a blood sample.

Breath testing equipment, sold under the trade names Breathalyzer or Intoxilyzer must be properly calibrated, maintained and the operator must be trained to administer the test to ensure that the number displaying on the machine is an accurate approximation of your BAC.

Recently, questions have been raised in relation to breathalyzers used in Massachusetts, where a potential software error with the calibration may have indicated that the machines were properly calibrated when they were not.

The state prosecutors informed defense attorneys in five cases that there was potentially a problem with the devices. And this may be the tip of the iceberg, given that the state has 350 of the machines and they may have been used in thousands of DUI stops.

Sophisticated technology is fragile. It is often subject to software bugs and the more complex, the more things can go wrong. With all of the negative consequences of a DUI arrest and conviction, it is wise to seek legal assistance to challenge the accuracy of any test. If a breath test is incorrect, you are the one who pays the price.

Source:, “Public owed an explanation on breathalyzer glitch,” April 27, 2015

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