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Devices Used for Breath Tests: Are They Accurate?

Devices Used for Breath Tests: Are They Accurate?

Devices Used for Breath Tests: Are They Accurate?

Oklahoma law enforcement officers administer breath tests to suspected drunk drivers, but the accuracy of those tests has been questioned repeatedly. Determining whether breath tests are accurate requires an understanding of what device is used, how it works, how it is maintained, and how tests are administered.

The breathalyzer used in Oklahoma is called the Intoxilyzer 8000, an older model in use for over 10 years in the state. Breathalyzers like the 8000 work on a light absorption theory. You breathe into the end of the device and your breath is captured in a chamber. A light bulb that emits infrared light shines through the captured air. Any alcohol molecules present in the air absorb a known amount of infrared light. As a result, some of the light will not reach a sensor at the end of the chamber. The device calculates how much light was sent by the light versus how much was received by the sensor to determine an alcohol concentration.

The breathalyzer relies on several assumptions that can be challenged in court. For example, the devices’ science assumes that each driver has 2100 parts of alcohol in their breath for every 1 part of alcohol in their blood. This is not true for every person. Some people have naturally lower breath/blood ratios. Further, drivers are supposed to take a deep breath before breathing into the device, so that the sample captures air from deep within the lungs where the exchange of alcohol molecules from blood to breath takes place. However, variances in the lungs, as well as alcohol from the mouth, throat, and stomach, could affect the test results. Another source of error is light absorption by molecules with a similar chemical structure to alcohol molecules, which could skew test results. There is some evidence that diabetics have higher acetone levels that could affect breath tests, and substances present in the environment may enter the testing chamber as well.

The Oklahoma Board of Tests enacts the rules that dictate maintenance of breathalyzers used by law enforcement. The current set of rules are extremely detailed, describing testing of the devices, maintenance logs, calibration, and more. However, sometimes these rules are not followed, leading to potential challenges of the device used to test a driver’s breath.

Facing your first court appearance and need an attorney for DUI charges in Oklahoma? Seek out the attorney who is in court nearly every day and teaches other attorneys and law enforcement about sobriety testing techniques. Clint Patterson, Esq., of Patterson Law Firm, a former Tulsa prosecutor now using his trial experience and expert-level knowledge of DUI science to defend drivers, has the experience and the insight to evaluate the strengths and weaknesses of your case. To schedule a case evaluation, visit Patterson Law Firm online or call Clint’s office at (918) 550-9175.