The (In)Accuracy of the Breath Test Machine
The (In)Accuracy of the Breath Test Machine
The Rhode Island Department of Health has approved only one (1) Breath Test Machine for Rhode Island. It is named the Intoxilyzer 5000, and it’s nowhere near as impressive as it seems. In fact, once you learn about the “science” behind it, you’ll wonder why anyone, let alone the police, relies upon its results.
The Intoxilyzer 5000 is the Breath Test Machine used throughout Rhode Island to “test” drivers arrested under suspicion of DUI. It’s commonly referred to as the Breathalyzer. It’s merely a computer based on ancient technology. For example, it’s “brains” consist of a Z-80 microprocessor introduced in 1975 for first home computers. If you’re old enough, this means it’s based on the same technology Radio Shack used to market the TRS-80 in the late 1970s and early 1980s.
The Breath Test Machine works on the theory of infrared absorption. An arrested driver is directed to blow into a breath tube which leads to a breath chamber cylinder. At the risk of getting too technical, the infrared light causes the alcohol molecules to “absorb” the light. The Breath Test Machine then “reads” the breath sample, compares it to a pre-designated solution sample, and “converts” the breath sample into an amount for us to understand.
This all sounds very technical and scientific, but the basic fact remains that it is not.
The Intoxilyzer 5000 manufacturer does not even pretend to claim that the machine is accurate. For example, the Intoxilyzer 5000 manual clearly “disclaims” that the machine is warranted for accurate and reliable breath testing. If the company that makes the Breath Test Machine does not guarantee accuracy, why should anyone believe it is? Moreover, the manufacturer designed the Intoxilyzer 5000 to be re-calibrated after every use, but the Rhode Island Department of Health requires re-calibration only once a month, regardless of how many times a Breath Test Machine is used.
Not only is the Intoxilyzer 5000 technology and accuracy questionable, but police officers can influence the results of a Breath Test. By doing so, they can cause inaccurately high readings. For example, it is not uncommon for a police officer to require a driver to blow until the Breath Test Machine’s tone stops. This instruction is misleading because the Breath Test Machine’s tone will not stop until the driver is out of breath.
The average human lung holds about five thousand (5000) cubic centimeters of air. The Intoxilyzer 5000 holds only eighty (80) cubic centimeters. If a driver “blows his lungs out”, the Intoxilyzer 5000 reads only the last breaths. This represents approximately 1% of the total breath actually blown. This is unfair because these last breaths contain the highest alcohol concentration, which produces inflated blood alcohol concentration results. In fact, the last part of the breath can be over 50% above the alcohol level. Therefore, a Breath Test result of .14 taken from the last part of the breath may indicate that the blood level is only 0.09.
Here are some other legitimate complaints about the Intoxilyzer 5000:
(1) If the Breath Test is not taken exactly as the Intoxilyzer’s manufacturer prescribes it will not accurately measure blood alcohol concentration. One of the main reasons for Breath Test inaccuracy is the presence of residual mouth alcohol. While the machine is supposed to measure how much alcohol is in the lungs, any residual mouth alcohol will result in an artificially high reading.
(2) The temperature of a driver’s breath can produce inaccurate results. The Intoxilyzer 5000 assumes a driver’s breath is ninety three (93) degrees Fahrenheit. Studies have demonstrated that the real average breath temperature for drivers arrested for DUI is closer to ninety six (96) degrees, with some as high as ninety nine (99) degrees. This alone would mean that the result of the test would be between 10% and 20% higher than it really is.
(3) Each driver eliminates alcohol or metabolizes it at different speeds, but the Intoxilyzer 5000 “assumes” everyone is the same. Therefore, a driver who eliminates alcohol more slowly than “average” will have a higher blood alcohol concentration, regardless of the alcohol’s effects on the driver’s ability to operate a motor vehicle. This is because the Intoxilyzer 5000 assumes that a driver is “post absorptive” meaning that alcohol is no longer being absorbed into the system. Drivers with a “slow” metabolism might still be absorbing alcohol by the time the test is taken. If so, it will produce a blood alcohol concentration result higher than it should.
(4) Belching, hiccupping or vomiting prior to the Breath Test is hugely important because they increase the amount of breath alcohol. A driver should not be tested for at least fifteen (15) minutes after belching, hiccupping or vomiting because these events increases the amount of alcohol on the breath. The Intoxilyzer 5000’s manual requires the officer to constantly observe the driver to ensure he has not belched, hiccupped or vomited within fifteen (15) minutes of the Breath Test. Constant observation is a rule that the officer must follow. If not, the Breath Test results may be inaccurate.
(5) Blood in a driver’s mouth may increase the blood alcohol concentration result.
(6) Experiments have shown that the Intoxilyzer 5000 has produced false positive results for test subjects who ingested bread and yeast, but not alcohol.
(7) Studies have shown that placing the power source for the Intoxilyzer 5000 too close to other devices that emit radio waves casts doubt upon its accuracy.