The breath card will be attached to every DWI case and most attorneys go directly to the "Subject Test" or the "BAC" reading to determine what their client is being charged with. However the "Cal.Check" and the "Air Blank" or "Room Air" readings and the time at which they are run can tell you a significant amount about how the test was run. And can even imply that there may have been contamination by multiple blows. Especially if there is a significant gap between the last "Air Blank" and your clients actual test and by gap I mean minutes because the card prints the exact time each portion of the test was conducted. I've seen as much as 3-6 minutes between when the machine read its last Air Blank and when it got a result from my client. On the face this implies that there were multiple blows because there would be no other reason for such a delay. This can cause significant contamination from mouth alcohol and give false high readings.
Look at the Maintenance Records.
If the DA gives you maintenance records of the instrument in question review it carefully. If they don't I generally subpoena it. Many precincts have no procedure for the frequency of maintenance and seem to do it on an ad hoc basis. You want to know what maintenance is done, why, how and by whom. This is a fountain of cross examination material. For example if the machine went 6 months between calibration checks (which I've seen) its almost impossible for a breath technician to be able to testify how often that machine has been used and the consequences of that. Also you will want to know why the specific maintenance was performed and how close to your clients test was it conducted.
Understand mouth alcohol and how the machine tests or fails to test it.
The intoxilyzer 5000 and 5000en detects "deep lung" alcohol and correlates that to a likely reading of blood alcohol concentration pursuant to a chemical theory called "Henry's Law". However, mouth alcohol is different. Mouth alcohol can be traces of ethanol in saliva or remnants or traces of chemicals in the mouth that do not fall under Henry's law. The machine uses what is called a slope indicator that detects initial mouth alcohol and continues to measure until it gets a reading of solid deep lung alcohol that takes longer to exhale. However, the slope indicator requires a 7 second blow to function correctly and there is significant research that it doesn't function properly. There are procedures police use to negate this factor but often they are not understood or followed.
Understand calibration checks.
Although the manual of the intoxilyzer 5000 and 5000en state that the machine is self calibrating, there are methods to independently calibrate it. Furthermore, many jurisdictions require independent calibration checks. To conduct these an operator must connect another device called a "Breath Alcohol Simulator" to the intoxilyzer. They then fill it with a simulator solution which is a predetermined ethanol/distilled water mix that is heated to create a gas which will generate a predetermined reading. You will want to know how this solution is prepared and by whom. You will also want to look at maintenance of the actual simulator and not just the intoxilyzer. Also, I suggest subpoena the protocols for the creation of the simulator solution and have an expert review them for errors. If they cannot testify to calibration, the DA may not be able to meet their burden in your respective jurisdiction.
Don't forget what is actually being tested.
All jurisdictions determine intoxication readings as being "blood alcohol tests" but don't forget that the intoxilyzer 5000 is not testing blood. It is testing breath and correlating it to blood. This means it is an inferential science or a science that is "based on inference" because you are not testing the actual substance which would be blood. There are always problems with inferential science because the correlation can be caused by significant amounts of contamination and other factors the machine can't detect. Too often DA's and even defense attorneys treat the BAC reading from a breath testing device as if it were measuring blood. Always remember that it is not.
Additional resources provided by the author
"Handling The DWI Case in New York" by Peter Gerszensang and Eric Sills
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