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The Serious Problems with Texas’ Breath Test Program

In my last trial, Tarrant County Criminal Court no.2, cause no. 1528525, the State’s expert readily conceded facts about Texas’ breath test program that are unacceptable.  

(fig. 1) The Intoxilyzer 9000

First, The Texas Department of Public Safety, a law enforcement agency,  runs the breath test program for the entire state of Texas. The Scientific Director for Texas DPS comes up with the regulations and oversees the program.  For scientific integrity, a law enforcement agency should never be in charge of forensic, scientific evidence. There are no checks and balances in this system. Power is very dangerous when it all rests in one body. Accordingly, there is a direct conflict of interest allowing the police to be in charge of forensic testing. President Barack Obama created a National Forensic Science Commission to come up with national standards for forensic science. After President Trump took office, he destroyed this body.  It is unwise and unsafe to allow law enforcement agencies to come up with their own standards. Therefore, we should leave science to the scientists.

The Intoxilyzer 9000

Second, Texas is now using the Intoxilyzer 9000. (fig. 1). CMI in Kentucky manufactures this breath alcohol estimator, also known as a breathalyzer. When purchased, it comes from the factory set to factory calibration. However, Texas DPS requires “in-house” re-calibration of each machine. If the manufacturer is producing an accurate breathalyzer, this is not necessary. If the manufacturer is producing an inaccurate breathalyzer, it is not acceptable that Texas uses these machines. This begs the question: What about the other problems in the machine that don’t relate to calibration?


Finally, Calibration should always have traceability. For example, if I calibrate my scale at home and decide that all scales should be judged for accuracy based on my self calibration, it is incumbent that I prove my method is based on accuracy that is traceable. The United States has a department for traceability of measurements, known as the National Institute of Standards and Technology (NIST).  In Texas, individual breath test technical supervisors are allowed to create their own reference solutions and they verify it by testing it on their own labs’ equipment (other breath test estimators or in house gas chromatography machines).  This is unacceptable, particularly when there is no independent, outside scientific group responsible for the estimators’ calibration. 

These are just the basic premise problems with Texas’ programs. The Texas Breath Testing program lacks accountability. Therefore, until there is separation between law enforcement and forensic science, we cannot expect accuracy. It is a fallacy for people to overlook foundational problems of breath testing and render life threatening decisions, such as jail or prison, among other possible consequences.

-Mimi Coffey

More about Mimi Coffey

When people look for a Top DWI Attorney or Best DWI Attorney, they look for experience, certification, and respect in the legal community. Mimi Coffey is a nationally-renowned trial attorney, board-certified in DWI by the NCDD. She has been practicing for over 24 years and is an author of multiple DWI Defense textbooks. She is also a national and state-wide lecturer on the law.

The Coffey Firm handles a wide variety of cases, including Unlawful Carrying Weapon (UCW), Assault (including family violence), Theft and Possession charges.

Mimi is also listed on several “top” directory listings such as DWI Lawyers for Wise County, DWI Lawyer Tarrant CountyDWI Lawyer Dallas County, DWI Lawyer Collin County and DWI Lawyer Parker County. Mimi is a caring DWI Lawyer in DFW, She is also involved in the Texas Tech School of Law foundation and enjoys using the skills she has developed to give back to the community.