Guest Column

A Geek's Eye View: Understanding New Jersey's Breath Test Machine


Last month our office attended a 16 hour training course presented over 2 days by the manufacturer of the Alcotest 7110 MK III-C , Drager Safety Diagnostics. The machine detects breath alcohol for establishing intoxication in DWI cases throughout New Jersey.  The course was presented by Hansueli Ryser, Drager Safety Vice President. Mr. Ryser testified before the New Jersey Supreme Court in the seminal case, State v. Chun, where the scientific reliability and accuracy of the Alcotest machine was reviewed. The Supreme Court established certain guidelines and safeguards that must be met before the results of the machine could be admissible as evidence of intoxication.  The course provided a similar level of training to that of which Alcotest Coordinators receive.  The course provided our office with hands on training with the Alcotest Machine, allowing us to act as operators and perform alcohol breath tests on fellow classmates.  This course is only open to 20 people and was taught 4 times before.   Our office was honored to be one of 120 individuals to receive this type of hands on training with the Alcotest Machine employing the current version of software employed in all New Jersey machines, Version 3.11.  The training was very technical wherein the mechanics of the machine were explained and discussed in meticulous detail.

At the course, our office learned about the history of breath test technology and the history of the types of breath testing technology the machine employs.  The Alcotest Machine uses Electro Chemical (EC) technology and Infrared (IR) technology when obtaining breath alcohol results.  Simply put, the breath sample is introduced into a chamber, where energy (light) is introduced on one side and an energy (light) detector measures and compares the amount of energy on the opposite end of the chamber.  The alcohol molecules absorb some of the light introduced into the chamber, thereby changing the amount of light energy transferred across the chamber.  The scientific community explains this absorption with the Beer-Lambert Law, which explains that energy transmitted through a defined path length (the sample chamber), containing an absorbing substance (ethanol molecules), the transmitted energy (the light) will proportionally decrease with the increase in concentration of the absorbing substance (ethanol).

The Electro Chemical sensor system also measures the same breath sample from inside the chamber.  Once ethanol reaches the sensor, a chemical reaction is triggered.  The resulting current is used to determine the amount of alcohol in the breath sample.  

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The machine compares the results from both the EC and IR paths to ensure they are within tolerance range of each other.  Moreover, the breath machine requires that certain conditions be met before it can produce a result.  These conditions were discussed and decided in the seminal case, State v. Chun.

Our office is familiar with the procedures and protocols in these types of cases which defenses can be raised and challenged in open Court.  Experts that we routinely use in defense of our DWI cases were also in attendance at the seminar.  Due to our hands on exposure and familiarity with the Alcotest machine, we provide an in-depth review of the State’s documents to investigate whether all procedures, protocols and conditions were met, and search for any available defenses.

 The Guest Column is our readers' opportunity to write about a given issue or topic in an in-depth and educational manner.

The opinions expressed herein are the writer's alone, and do not reflect the opinions of or anyone who works for is not responsible for the accuracy of any of the information supplied by the writer.

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