How the defendant’s DUI attorney attacks “minor problems” with the Intoxilyzer

Last Modified: June 18, 2024

How the defendant’s DUI attorney attacks “minor problems” with the Intoxilyzer

In the trial of a drunk driving case, the closing argument can be vital. Closing argument is the last chance for the defendant’s DUI attorney to address the jurors. The attorney must make the closing count.


Finding a good analogy to include in the closing argument can often make a big difference. An analogy works well because it helps jurors to visualize what is otherwise a hard concept to understand. Suppose the prosecutor has characterized problems with the Intoxilyzer breath test machine as “minor problems.” The skilled defense attorney can use an analogy to attack the prosecutor’s case. Here is an example:


“Ladies and gentleman, you heard from the witnesses as to certain inconsistencies, deviations and problems with the maintenance and calibration of the Intoxilyzer administered in this case. Now the prosecutor tells you that they are small issues raised by the defense as a smokescreen; that a bad test or two, in the entire logs of the Intoxilyzer, do not matter.

This reminds me of when my wife and I were shopping for our first house. We knew that it was a huge investment so we were taking our time. Finally we found what appeared to be the perfect house for us. A beautiful Victorian with lots of detail and plenty of room to expand as our family would.

During the final walk through, I noticed a couple of termites in the corner. Upon pointing this out to the agent of the owner, he squished them, turned to me and said problem solved.

Needless to say we did not buy that house. Those two termites were just the easiest to see examples of some fundamental problems. Just as with the house, the examples of problems on the Intoxilyzer used in this case are only the tip of the iceberg. Clearly there is a major problem with the machine and with the prosecution’s case. Ask yourself if this is a house you would buy.”


Here is another brief example of how the DUI defense lawyer can use an analogy during the closing argument:


“You are not feeling very well so you visit your doctor. The nurse comes in and takes your temperature. It is a little high. Then she notices that your pulse is rapid and that your blood pressure is up. The doctor comes in, looks at this information but says, “you are fine.” Are you satisfied? Hopefully not. You would want to get a second opinion, or at least to discuss the symptoms. But not with this doctor—here the ‘expert’ says he knows best and you should just go home.

But will this doctor be answerable when in the morning you cannot get out of bed? No way. You see it is not his fault if he is wrong. He just relied on the information and took his best guess.”


To help the defendant defeat a drunk driving charge, a knowledgeable and experienced DUI attorney can use analogies and other advocacy techniques to help jurors understand the defects in the prosecutor’s case.

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