New Jersey DWI Attorney John Menzel

What Is The Procedure For The Evidentiary Breathalyzer Test In A DWI?


New Jersey uses an instrument called the Alcotest model 7110 manufactured by a company called Draeger Safety incorporated. A person arrested for DWI is taken to a police station, where a police officer will read a standard statement to inform the person of their rights and obligations with regard to breath testing. The officer conducting the breath testing should make a notation of when he or she starts watching you, because that officer has to observe the arrestee for at least 20 minutes before that person submits samples. This observation period is intended to make sure that the breath testing subject does not burp, belch, regurgitate or ingest anything. The idea behind that 20-minute observation period is to assure that nothing contaminates the breath sample.

The theory behind breath testing in New Jersey is that the amount of alcohol in breath is equivalent to the amount of alcohol in your blood. If anything contaminates the breath sample, it throws off this basic assumption. The officer then instructs the subject to take a long continuous exhalation into the breath tube until told to stop. In New Jersey, these breath testing instruments are programmed to accept samples of a certain volume delivered over a certain duration. The minimum volume of the sample is supposed to be at least 1.5 liters, and the minimum duration of the sample is supposed to be at least 4.5 seconds. Assuming that sample is delivered continuously without any interruption, the instrument should accept the sample. The instrument is programmed to recognize certain error conditions, such as an uneven flow of breath as it is introduced into the machine or the presence of mouth alcohol or other interfering substance. If the instrument detects such a condition, it will flag that sample as being inappropriate and either prompts a new test or a new sample to be submitted.

In New Jersey, two samples are taken, and each sample must yield a measurement within 0.01 or 10 percent of each other, whichever is greater. The breath is being measured using two different technologies. The first is by infrared spectroscopy [“IR”], which basically measures the amount light of a certain wavelength that is absorbed by the sample. The other is electrochemical analysis [“EC”], meaning the amount of electrical energy created by the breakdown of the sample as if it was a battery being discharged. By measuring the discharge in that battery (also referred to as a fuel cell) and comparing it to the amount of infrared energy absorbed by the sample, and if the IR and EC measurements agree closely enough (i.e.–within 0.004 of each other), the instrument will accept that sample and translate that absorption and that electrical discharge into an alcohol level.

Is The Observation Period A Critical Step In The Testing Process?

The observation period is an essential step in the testing process because if the 20-minute observation period is not adequately established in court, the breath test results will not be admitted into evidence.

Can The Observation Period Be Utilized As A Means Of Possible Defense In A DUI Case?

An officer’s failure to observe a breath testing subject for at least 20 minutes immediately before the subject submits a breath sample is a defense to the admission of the breath test result. There are certain things a defense attorney should look for in the police report. One is whether there is a record of when the observation period began, for example. If there isn’t, it gives rise to questions about whether that 20-minute observation period was observed at all. Sometimes an officer will record times, but instead of using the clock on the Alcotest instrument, they will use another clock. One thing we say about this is this: if you use one clock, you always know what time it is; but if you use two clocks, you’re never sure. A lot of times officers will rely upon the dispatch clock to note when they are beginning the 20-minute observation period, not really thinking about or realizing that the dispatch clock is not synchronized with the Alcotest clock. This can be brought out during cross-examination.

Some departments videotape the breath testing process, enabling the court to see that, while officers will write down that they watched the subject for 20 minutes, they forget that they actually left the room for a short period of time, thereby violating that 20-minute observation requirement. A court should exclude such a breath test. Again, this observation period is extremely important because it ensures that the breath sample was not contaminated.

This requirement was first recognized by the New Jersey Supreme Court in 1990 in a case called State v. Downie and was reinforced in State v. Chun, the case validating the Alcotest 7110 for use in New Jersey. By preventing a claim of contamination, this 20-minute observation requirement maintains that relationship between breath alcohol content and blood alcohol content.

For more information on Evidentiary Breathalyzer Test In DWI, a free initial consultation is your next best step. Get the information and legal answers you are seeking by calling (732) 899-1899 today.

John Menzel, J.D.

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