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Artificially High Readings and False Positives in Florida DUI Cases
By: Michael Dye
Posted on : August 20, 2012   Views : 1262
Often the most damaging evidence in any DUI prosecution is the results of a breath test. In an attempt to convict an individual of DUI, the State will present a Breathalyzer result of .08 or higher as evidence that an individuals blood alcohol concentration was over the legal limit. You will need to note, that a Breathalyzer test is what is considered an \"indirect test.\" The reason that the Breathalyzer is an indirect test is because it purports to measure blood alcohol concentration by use of something besides blood. Obviously the Breathalyzer uses air from the lungs so as to determine blood alcohol concentration. In order for an indirect test to be accurate there needs to be a correlation between the quantity of alcohol within exhaled breath and blood within the circulatory system. One of many faulty assumptions of the Intoxilyzer 8000 is that the result given does not take into account numerous variables. Unfortunately, in a DUI case, once the State has laid the evidentiary foundation required to admit the test result, the DUI defense attorney\'s job is to clarify how the result was obtained. This is often what is called a \"burden shift\" and is otherwise unconstitutional in every other type of criminal case. It is said that the burden of proof for the State for a DUI case is lower than any other kind of criminal case. DUI attorneys commonly call this the \"DUI exception to the Constitution.\"The design of the Intoxilyzer 8000 is designed to prevent common occurrences from producing an inaccurate result. One of several issues frequently raised is the issue of mouth alcohol impacting the results of the test. Essentially, mouth alcohol is alcohol that is not exhaled from the lungs, but rather alcohol in an individuals mouth. That seems simple enough. In an effort to eliminate a false high test result and ensure that the result is admissible in a DUI prosecution, the officer administering the test is required to conduct a 20 minute observation to insure that the person doesn\'t regurgitate and/ or vomit which can cause alcohol in the stomach to go to the mouth. In addition to requiring a 20 minute observation period, the Intoxilzyer 8000 includes a \"slope detector.\" The slope detector is designed to prevent mouth alcohol from giving an artificially high reading. The bottom line is the slope detector does not work. In addition to regurgitating, vomiting and belching, mouth alcohol could be influenced by dentures and other items in the mouth. Recently a portable breath test result was excluded in the case of State of Illinois vs. Mark Ditka due to the fact that he was chewing tobacco immediately before he was asked to take the portable breath test. Chewing tobacco or snuff contains a byproduct of alcohol called acetaldehyde. Due to the way that certain breath testing machines read the infrared spectra, the machines can easily confuse ethyl alcohol with acetaldehyde.The manufacturers of infrared breath testing equipment have gone to great lengths in an effort to remedy false positives and/or artificially high readings. The machines may also render false positive results on account of exposure to certain hydrocarbons. Regarding the older model Intoxilyzer 5000, there exists some debate as to whether a person will register a result if exposed to a compound called toluene. The Intoxilyzer 5000 reads the infrared spectra produced at 2 points so as to eliminate false positives for other hydrocarbons. An article entitled \"The Response of the Intoxilyzer 5000 to Five Potential Interfering Substances\" is a peer reviewed and published article which indicates that the Intoxilyzer 5000 will yield a positive result for alcohol based on exposure to toluene. The article was written by JP Caldwell and NP Kim of the Department of Chemistry, University of Waikato, Hamilton, New Zeland. A contrary position was taken in the article \"Toluene and the Intoxilyzer 5000: No Response to Concentrations Found on Human Breath\" written by PL Glover. Additional factors that been shown to effect the readings of infrared spectroscopy breath testing devices include acetone in the breath, asthma, altitude, blood contained in the mouth.......the list can go on for an awfully long time. However, it is rather clear that these machines will render false positives and artificially high readings in certain circumstances. Since the test result is a vital piece of evidence in any DUI proceeding, it is important to examine not only the piece of paper with the number, but the data and records from the individual machine in order to see exactly how that number was reached.
Michael Dye is a Broward County DUI Attorney in Fort Lauderdale, Broward County, Florida. For further information, please call (954)745-5848 or visit