How to Fool a Breathalyzer
Posted: Monday, January 02, 2006
by Lawrence Taylor
The Law Offices of Lawrence Taylor
Want to trick a breath machine into a low test result? Or make sure that you're not causing a fa
The simple fact is that these breath machines which determine guilt or innocence in DUI cases are not exactly the reliable devices that law enforcement would have us believe. There are dozens of factors that can cause false test results. An example of that unreliability is the fact that the results will vary depending upon the breathing pattern of the person being tested. This has been confirmed in a number of scientific studies.
In one, for example, a group of men drank moderate doses of alcohol and their blood-alcohol levels were then measured by gas chromatographic analysis of their breath. The breathing techniques were then varied. The results indicated that holding your breath for 30 seconds before exhaling increased the blood-alcohol level by 15.7%. Hyperventilating for 20 seconds immediately before the analyses of breath, on the other hand, decreased the level by 10.6%. Keeping the mouth closed for five minutes and using shallow nasal breathing resulted in increasing the blood-alcohol level by 7.3%, and testing after a slow, 20-second exhalation increased levels by 2%. ("How Breathing Techniques Can Influence the Results of Breath-Alcohol Analyses", 22(4) Medical Science and the Law 275.)
Dr. Michael Hlastala, Professor of Physiology, Biophysics and Medicine at the University of Washington has gone farther and concluded:
"By far, the most overlooked error in breath testing for alcohol is the pattern of breathing... The concentration of alcohol changes considerably during the breath... The first part of the breath, after discarding the dead space, has an alcohol concentration much lower than the equivalent BAC (blood-alcohol concentration). Whereas, the last part of the breath has an alcohol concentration that is much higher than the equivalent BAC. The last part of the breath can be over 50% above the alcohol level... Thus, a breath tester reading of 0.14% taken from the last part of the breath may indicate that the blood level is only 0.09%." 9(6) The Champion 16 (1985).
Many police officers know this. They also know that if the machine contradicts their judgement that the person they arrested is intoxicated, they won’t look good. So when they tell the arrestee to blow into the machine’s mouthpiece, they’ll yell at him, "Keep breathing! Breathe harder! Harder!" As Professor Hlastala has found, this ensures that the breath captured by the machine will be from the bottom of the lungs, near the alveolar sacs, which will be richest in alcohol. With the higher alcohol concentration, the machine will give a higher -- but inaccurate -- reading.
Lawrence Taylor is the senior member of an AV-rated law firm of San Diego DUI lawyers practicing drunk driving defense exclusively.
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Top-level comments on this article: (3 total)I did not find any information regarding how to fool a breathalyzer. All I found was an advertisement for a law firm who would want a person to fail the breathalyzer so that that person will tend to need a lawyer.
I think this article is very useful for anyone using this information for reasearch. That way people will be able to see the ups and downs of a breathalyzer.
I thought it gave a good insight into the dreaded breathalyser. Atleast I know that when they keep telling you to 'keep going breathing harder', DONT is what I personally say. Also not to low or they will make you do it again. I think its about stopping your breathing b4 it becomes concentrated with alcohol. someone suggested to moi that havin a 2 pence piece in ur mouth b4 blowin will affect reading. something to do with the copper or something but dont take my word 4 it cause im not sure. But most of all Try not to drink and drive and we wont need a cure for the problem if we can prevent it. A stich in time saves nine.
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