How the Intoxilyzer 5000 works and Defenses to DWI

The Intoxilyzer 5000EN operates on a principle of infrared light absorption.  An infrared light bulb shines through the sample chamber at one end while a light detector is positioned on the other end of the chamber.  Alcohol absorbs infrared light.  We can’t see infrared light; it is too far out of the visible light spectrum.  However, the machine can detect how much infrared light is absorbed by alcohol.

The amount of alcohol in a breath sample is minute; no more than what would fit on the head of a pin.  Therefore, if the machine is malfunctioning and miscalculating the amount of alcohol for the test subject, those miscalculations are greatly magnified equating to an overly inflated BAC result.

The machine is not alcohol specific.  Rather, it will label any chemical compound that has the methyl chain within its molecular structure.  That means that ethyl alcohol (what we drink), which is what impairs your ability to drive may be confused with paint thinners, acetone, propane, butane, gasoline, propylene, methane, ethane, menthol and many other substances that contain the methyl compound in their molecular structure.  That means that if you are exposed to paint thinners over a long period of time (maybe you are a furniture restorer) and you have a beer after work, you may test out as a .12% because of paint thinner fumes you’d been breathing in all day.  That’s because the machine can’t tell the difference between alcohol you drink (like a beer) and paint thinner fumes that you’re exposed to.  This argument is called an interfering substance defense and is based totally on scientific principles.

Another problem with the Intoxilyzer 5000 is that people who are diabetic are at a high risk of being wrongly charged with DWI.  When a diabetic is in ketoacidosis, the person is producing keotones which in turn are expired as acetone on the breath.  While the machine can detect acetone by itself, it cannot differentiate acetone mixed with alcohol in a breath sample and instead, adds them together.  This means that a diabetic ends up being wrongly prosecuted for DWI when he merely has a medical condition.

The machine is not very accurate.  When you give a breath sample, the sample results do not have to match.  They only have to be within .02% of each other.  That means a .08% BAC result could be as low as .06% or as high as .10%.  I guess that’s what they mean by “good enough for government work.”

A person’s internal body temperature can cause the BAC to increase through no fault of his or her own.  That’s because the Intoxilyzer cannot determine a person’s temperature and assumes that everyone has the same breath temperature.  Other machines do take into account a person’s breath temperature when calculating a BAC; but not the Intoxilyzer.

The machine is gender biased.  Because females naturally have a higher body fat percentage than males of an equal body weight; and because alcohol only distributes to the watery parts of the body (blood, muscle, organs… NOT body fat), a female will almost always have a higher BAC than a male of the equal body weight.  That is due in large part to the female’s higher body fat percentage.  Does that sound fair to you?  I didn’t think so.

These are just a few of the scientifically and medically verified defenses to the Intoxilyzer 5000.  A good DUI attorney should be well versed in both the law and science of DUI defense.  This is a highly technical field of the law and it is not an area where a lawyer can just “jump in” and handle a few DUIs along with his regular criminal practice.  This is an area of the law that calls for specialization.