After years of using breath-testing devices in order to help an officer determine whether a suspect should be arrested for driving under the influence, the Tennessee Highway Patrol (THP) elected not to use breath-testing as a tool. This may have been due to the law in existence at that time which could be interpreted to limit the number of times a suspect could be requested to provide a testing sample, but the statute itself was changed years ago to allow for multiple samples to be submitted.
Currently, WSMV4 reports that the state-wide Law Enforcement agency is apparently now using preliminary breath-testing to help make the arrest-decision. This policy change is likely due to the large number of people arrested for DUI who provide blood samples that later verify they are not under the influence of any intoxicant.
There is, however, another problem with this decision. Preliminary breath tests, in general, are not admissible in court due to calibration issues and the potential for external interferents such as radio frequency interference. Other issues can exist as well. Using an average lung capacity to estimate a person’s blood alcohol only starts the potential list of problems. Body temperature, sampling while alcohol is still being absorbed, mouth alcohol, and non-specificity or among other potential issues regarding the accuracy of these devices.
In this author’s opinion, blood alcohol testing, if performed correctly, is the “gold standard.” The problem with excessive number of innocent suspects arrested is due to the field sobriety “tests” that are used to make the arrest decision, as well as the lack of training of the officers using the current, unreliable, field sobriety tests.
About the Author: Steven Oberman has been licensed in Tennessee since 1980, and successfully defended over 2,500 DUI defendants. Steve was the first lawyer in Tennessee to be Board Certified as a DUI Defense Specialist by the National College for DUI Defense, Inc. (NCDD). Among the many honors bestowed upon him, Steve has served as Dean of the NCDD and currently serves as chair of the National Association of Criminal Defense Lawyers DUI Committee.
Steve is the author of DUI: The Crime & Consequences in Tennessee, updated annually since 1991 (Thomson-West), and co-author with Lawrence Taylor (1942 – 2023) of the national treatise, Drunk Driving Defense, 9th edition (Wolters Kluwer/Aspen). Steve has served as an adjunct professor at the University of Tennessee Law School since 1993 and has received a number of prestigious awards for his faculty contributions.
He is a popular international speaker, having spoken at legal seminars in 30 states, the District of Columbia and 12 foreign countries. After being named a Fulbright Scholar, Steve was honored to teach as a Visiting Professor at the University of Latvia Faculty of Law (Law School) in the capital city of Riga, Latvia for a semester during 2019. In 2023, Steve accepted an offer to teach for a semester as a Visiting Professor at Eötvös Loránd University Faculty of Law in Budapest, Hungary. Steve was designated a Fulbright Scholar for a second time and taught American Criminal Law and American Trial Advocacy at The University of Ljubljana Faculty of Law in the capital city of Ljubljana, Slovenia for the 2024 spring semester. Since then, Steve taught American Trial Advocacy to Masters Students in Criminal and Criminal Procedure Law for the Winter Semester in 2025 at the Universidad Carlos III de Madrid Faculty of Law in Madrid, Spain and at The University of Gdańsk Faculty of Law in Poland during the winter semester of 2026. If you would like to contact the author, please visit his website at www.tndui.com. ↩︎
