Tuesday, October 8, 2024
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How do machines test for alcohol in breath?

Although three types of breath-testing estimators are approved for use in Arizona, the police only use one–the Intoxilyzer 8000© made by CMI, Incorporated, in Owensboro, Kentucky.
The Intoxilyzer 8000 uses Infrared Spectroscopy to analyze breath to create and estimated breath alcohol content. It does this by first projecting infrared (IR) light through a sample chamber at two IR detectors with only ambient air in the chamber. It measures the amount of IR light that strikes the detectors and sets up a baseline to compare to a subsequent breath sample.
Next, a person blows into the machine, filling the sample chamber with breath. The Intoxilyzer projects IR light through the breath sample at the detectors. The IR light excites the molecules in ethyl alcohol, causing the molecular bonds to bend, stretch and rock. This causes less IR light to strike the detectors. A difference in the amount of light which struck the detectors before and during breath samples is measured and a breath alcohol estimate is calculated by way of a secret formula known only to CMI.
The key to IR testing is that each organic molecule has a unique IR “fingerprint” which cannot be confused with any other molecule. While this may be true, neither the Intoxilyzer 8000 nor any other IR breath tester measure the entire molecule. Some IR breath testers measure up to five different IR wavelengths. The Intoxilyzer 8000 measures only two. By way of analogy, think of it as a roadmap. Your are told that I-10 passes through Tucson and crosses 18th Street and 22nd Street. Thus, any city through which I-10 crosses streets named 18th Street and 22nd Street is Tucson. At 2,460 miles in length, I-10 is the fourth longest Interstate Highway in the United States. Surely, somewhere along its route it passes through another city, crossing 18th Street and 22nd Street. Using Intoxilyzer IR technology, you would mistake that city for Tucson–and using Intoxilyzer IR technology, it can mistake other molecules for ethyl alcohol.

If you have any questions about this, or any other legal issue, please feel free to contact Nesci & St. Louis PLLC at (520)622-1222, or visit us on the web at www.AZDefense.com.

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James Nesci

James Nesci often defends cases well into the .30 blood-alcohol range. He has caught more than one police officer lying during cross-examination and some police officers have even refused to grant pretrial interviews to him without a prosecutor or their own counsel present. He was one of the lead attorneys on the Intoximeters® RBT-IV breath-testing issue in Southern Arizona which resulted in the suppression of breath tests in over 7,000 cases and the removal of the RBT-IV from the streets of Arizona. He also spear-headed the effort to obtain the manufacturer’s source code and software for the CMI Intoxilyzer 8000. Although the source code was never obtained, he almost single-handedly ground 90% of all DUI prosecutions within the City of Tucson to a halt for nearly three years and obtained breath test suppressions and dismissals in hundreds of DUI cases. In addition to “traditional” DUI cases which involve alcohol, Mr. Nesci is a recognized expert on the defense of DUI/Drugs cases. Whether they be legal-over-the-counter-medications, prescription medications or illicit drugs, such DUI cases are far more complex and present cutting-edge issues for the courts. He is qualified to administer Standardized Field Sobriety Tests under National Highway Traffic Safety Administration & International Association of Chiefs of Police Guidelines. In 2006, he was appointed Regent of the National College for DUI Defense, Inc. He was formerly the chair of the Curriculum Committee for the NCDD. Currently, he is the State Delegate Coordinator, a member of the Amicus Committee, Treasurer of the NCDD, Member of the Executive Committee and served as an oral argument judge for the Board Certification Committee. Mr. Nesci is the author of Arizona DUI Defense: The Law & Practice, a legal treatise written for DUI defense attorneys and published by Lawyers and Judges Publishing Company (now in its third edition) [www.lawyersandjudges.com]. In 1999 Mr. Nesci became a Sustaining Member of the National College for DUI Defense [www.NCDD.com]. In 2001, he was Board Certified by the National College for DUI Defense, Inc., which is a is recognized by the American Bar Association. He is one of only three Board Certified attorneys in the State of Arizona, and one of less than fifty Board Certified attorneys in the nation (as of January, 2012). Mr. Nesci has lectured from coast-to-coast for such organizations as The University of Arizona James E. Rogers College of Law, Arizona State University College of Law Alumni Association, University of Mississippi CLE Department, South Texas College of Law CLE Department, Arkansas Association of Criminal Defense Lawyers, Arizona Attorneys for Criminal Justice, Arizona Public Defenders Association, California Attorneys for Criminal Justice, City of Phoenix Public Defender's Office, Colorado Criminal Defense Bar, Florida Association of Criminal Defense Lawyers, Indiana Public Defender’s Council, Kansas Association of Criminal Defense Lawyers, Louisiana Association of Criminal Defense Lawyers, Maricopa County Bar Association, Maricopa County Public Defender's Office, Maryland Criminal Defense Attorneys Association, the Mexican-American Bar Association at Loyola, the National Association of Criminal Defense Lawyers, the National College for DUI Defense, the Nebraska Criminal Defense Attorney’s Association, the Nevada State Bar Association, the New York State Bar Association, the Ohio Association of Criminal Defense Lawyers, the Pima County Bar Association, the Pima County Bar Association Young Lawyer’s Division, the Texas Criminal Defense Lawyers Association, the Tucson City Public Defender’s Office, the Tulare County (California) Public Defender’s Association, the Utah Criminal Defense Lawyers Association, and the Washington Foundation for Criminal Justice. He has taught seminars on the subjects of Ethics, 4th Amendment Law, Drug Recognition Evaluations (DUI-Drugs/DRE), Cross-Examination, Trial Tactics, Jury Selection, Field Sobriety Testing, Driving Behavior, Blood Alcohol Calculations, Opening & Closing Arguments, Source Code Litigation, Frye & Daubert Challenges, Intoxilyzer 8000 Operator’s Course, Headspace Gas Chromatography, Blood and Breath Testing. He has represented former Supremes lead singer Diana Ross and Tampa Bay Buccaneers' Tight-End Jerramy Stevens on Extreme DUI charges and fitness guru Richard Simmons on an assault charge. Mr. Nesci lives in Tucson with his wife and twin daughters. He is an honorably discharged veteran of the U.S. Navy where he spent much of his time working as an electrician in the Philadelphia Naval Shipyards. His interests are traveling, fine wines, vintage port and fast cars. He is an amateur race car driver, an accomplished mechanic, and a Corvette fanatic.

One Response

  1. Good job in making your points well understood. Ignition interlocks are a great products that is available not only to offenders but to the public. The purpose of the device is to control and monitor vehicles driven by convicted DUI offenders, thus enhancing public safety.

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