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How Accurate Are Breathalyzers?

When a person is pulled over by police and an officer suspects they are driving under the influence of alcohol, the officer conducts a breathalyzer test. The driver blows into a device which then gives a reading estimating blood-alcohol content by measuring the alcohol in the individual's breath. This evidence is then used in the drunk driving charges against an individual if they are over the legal limit.

There are many issues that cause defense attorneys to question the accuracy of a breathalyzer test. Officer error in properly calibrating the breathalyzer is one of them. But what if the device itself is flawed?

One of the types of breathalyzers used by law enforcement departments throughout the United States is manufactured by a company called Draeger. The device has come under fire after an evaluation by the defense in a Washington DUI case. The research indicated that the Draeger breathalyzer has flaws that can produce incorrect test results. These findings have cast doubt on a vast number of DUI convictions throughout the country.

Unfortunately, the research in the Washington case remained inconclusive, as it was discontinued due to legal action by Draeger. Draeger's claim asserted a need to protect its proprietary source code as intellectual property, which it argued should not be subjected to potential misuse by the outside experts. As a result of this legal move by Draeger, the researchers were denied full access to necessary source code for calibration of the Draeger Alcotest 9510 equipment under evaluation. However, the experts' preliminary report clearly indicated flaws that could be expected to produce incorrect results in breath tests.

Problems Found In The Draeger Breathalyzer

A new effort to obtain and test the Draeger source code was made in in a 2015 Washington state DUI case. Access to the source code was granted, under very constrained conditions. The preliminary findings of the new examination found problems in the source code that are significant enough to produce an inaccurate outcome of breath test for alcohol. The report indicated issues including:

  • Failure to adjust for breath temperature fluctuations throughout the day-an issue that can result in as much as a 6 percent variable in test results
  • Questionable accounting and compensation for normal degradation of the fuel cell in the device that is designed to measure individuals' alcohol levels
  • Possible inadequate systems for routine recalibration based on frequency of use and operating conditions

Draeger Alcohol Breath Testing Remains In Wide Use

Despite adverse research findings and rampant uncertainties about the accuracy of the Draeger alcohol breath-testing device, the source code that drives the functioning of this particular police breathalyzer continues to be used throughout a number of states, and the validity of millions of arrests on DUI charges remain in question.

Researchers examining the device have consistently expressed skepticism that the Draeger Alcotest 9510 is capable of producing reliable measurements of breath alcohol. They have recommended that law enforcement officers use great caution in interpreting the Draeger device's results. Draeger has admitted that calibration, adjustment procedures, additional equipment, related materials, and the people performing the testing procedures are all factors in the accuracy of tests conducted using its devices.

These are all key issues that an experienced criminal defense attorney can examine in your case if you are facing a drunk driving charge.

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