New Jersey DWI Breath Testing Machine: Calibration of the Machine and Why It’s Important to Your Case

If you were arrested for a New Jersey DWI, and you submitted breath samples at the police station, your breath testing was done on a Draeger Alcotest 7110 MKIII-C machine. There are many components to a DWI arrest, and it is important to understand how each part can be challenged. For example, if the machine was not calibrated properly, the breath test results can be suppressed, or thrown out.

Calibrating the machine involves running several tests on it with different alcohol “simulator” solutions. The solutions must be heated to 34 degrees Celsius, plus or minus 0.2 degrees. This temperature is supposed to simulate the temperature of human breath, however, studies have demonstrated human breath to be closer to 35 degrees. This difference in temperature can cause more than 6% error in the ultimate breath test result.

Appropriate temperatures are determined using an external NIST traceable temperature probe. NIST is the National Institute of Standards and Technology, which establishes and maintains basic international standards of measurement. The temperature probe is used to ensure the proper temperature of the solutions just before the calibration of the Alcotest.

First, the machine is programmed with a 0.10% alcohol solution. This solution “tells” the machine what a 0.10% alcohol reading is, like programming a scale with a 10 pound weight. The scale is calibrated to read the 10 pound weight as 10 pounds. If the machine doesn’t then read within a specified range at the 0.10% level, it is reprogrammed with a different solution. This is known as the Part I Control Test.

There is also linearity testing done on the machine with 0.04%, 0.08%, and 0.16% solutions. The machine is tested twice with each of these solutions, and must read within an acceptable range of each of the solutions. If it doesn’t, the machine will be placed out of service. This is known as the Part II Linearity Test.

The third part of the calibration process involves the simulator solution that will now be used for subsequent testing with the machine. This is the Solution Change Report. This solution is good for 25 subject tests or 30 days, whichever comes first.

If any one of these processes is compromised, the testing in your case should be suppressed, or dismissed.

It is therefore critical to consult with a qualified DWI defense attorney who knows the specific processes of Alcotest machine. I represented the lead defendant in the case that decided the reliability of this machine, State v. Chun. The Chun case has set the standards for DWI defense and prosecution throughout the state of New Jersey.

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