PA DUI Breathalyzers – Understanding Accuracy and Calibration

The recent United States Supreme Court case of Birchfield v. North Dakota, has caused an increase in the use of the breathalyzer in DUI cases in Pennsylvania. In that decision, the Court said that while a search warrant is needed for a blood draw following the arrest for suspicion of DUI, a warrant isn’t necessary for a breath test because the intrusion on a person’s constitutional rights is much less severe. I have written previous articles on breath testing principles along with the Birchfield decision and I encourage you to read them. This article, however, focuses on the accuracy and calibration certifications for these devices.

Pennsylvania maintains 2 types of breath testing devices. Type A devices are the breathalyzers used to determine a person blood alcohol concentration or content (BAC) following an arrest or stop on suspicion of DUI. Type B devices are used to determine BAC for subsequent laboratory analysis; my focus here is on Type A devices.

Currently, most law enforcement agencies within the Commonwealth are using the Intoxilyzer 8000 in drunk driving cases. This device requires that the prosecution (Commonwealth) through the assistant district attorney, present certified records pertaining to the device’s accuracy and calibration. While accuracy and calibration are sometimes used interchangeably, it is important to understand that they are two separate certificates that the prosecution (assistant district attorney) must introduce to establish the admissibility of the Breath testing device along with its results.

Under Pennsylvania law, the accuracy inspection test refers to a series of five simulated tests using a simulator solution designed to give a reading of .10 conducted by a certified breath test operator within 30 days prior to using the breath test equipment to perform an actual breath test. Calibration refers to the performance of a series of 5 simulated tests on the device within one year of using the Breathalyzer to perform an actual breath test. One of these tests must use a simulator solution designed to give a reading of .10, another .05, and a third test a reading of above .10. The results of the accuracy and calibration test must be recorded and provided in pre-trial discovery

The simulator solution is an aqueous standard ethanol solution which, when equilibrated with air in the device produces an air-alcohol mixture of a predetermined concentration that is designed to give a specific reading on a Breathalyzer. These solutions have an expiration date and a critical area of attack for your criminal defense lawyer is sometimes the expiration of the solution which ultimately could alter the accuracy of the test results

With regards to the accuracy test, the device must be removed from service if one or more of the five tests yields a result less than .09 or greater than .109 or if the average deviation derived by adding the absolute value of the difference between the result of the five tests and the constant value of .10 divided by 5 exceeds .005. There is a similar cutoff calculation for the correct calibration of this device.

In addition to the calibration and accuracy requirement, the person administering the Breathalyzer must satisfy specific training and education requirements (30 hours of instruction) with the Pennsylvania Department of Health and the Pennsylvania Department of Transportation (PENNDOT).

For more information on drunk driving defense strategies, I encourage you to visit my free download section and check out my book—5 Ways to Fight & Win Your Pennsylvania DUI Case.