I just returned from the “Mastering Scientific Evidence” seminar in Dallas, Texas which was sponsored by the National College for DUI Defense. For 3 days I learned more about breath and blood tests than I already knew. Before the seminar I thought I had a pretty good handle on the issues, but now I feel much more in command of the principles of chemical testing and the fallacies behind the breath tests.
I had been to training seminars before where I watched as people who had no alcohol, whatsoever, in their systems blew significant results on the Intoxilyzer 5000 simply because they had white bread in their mouths, had recently rinsed with mouthwash or because there was a cell phone in the room. So, I knew that the machine did not work as advertised. However, we really picked the thing apart in Dallas, and I am even more convinced that people are pleading guilty and taking diversion in cases where they had not actually broken the law. That, of course, is a miscarriage of justice.
The Intoxilyzer 5000 was introduced in the early 1980’s. It relies on a z-80 microprocessor chip. The best known product to use the z-80 is the old Radio Shack TRS-80, one of the first personal computers in the early 1980’s. If you were around in 1976 whenthe z-80 was released, and in the subsequent years in which it was employed in the TRS-80 (also known as the “Trash-80), you know we are dealing with ancient technology.
The technology in the Intoxilyzer 5000 was all created and “tested” before the advent of such things as cell phones. Cell phones create radio frequency interference (RFI) which can cause phantom breath test results on the breath testing gizmo. Cell phones transmit constantly, even when they are not in use. If the phone is turned on, the phone is transmitting. The worse the cell phone reception, like in police stations and jails, the stronger the signal the phone transmits as it attempts to connect to the signal. Digital cell phones are far more powerful than analog cell phones, so this problem is getting worse not better.
The “new and improved” Intoxilyzer 8000 is no better than the 5000. I got to see and use one for the first time in Dallas, and it essentially has all the same problems of the old machine. The cell phone still created a false positive on the machine. So did the white bread. The scary thing about the white bread causing positive breath tests is that no one knows why it does so. Thus, no one knows what else in someone’s mouth, breath or system may also be causing false positives.
Another area in breath testing getting more attention is the role that temperature plays in testing. The concentration of alcohol in a vapor (like breath) is dependent on temperature. The higher the temperature, the higher the concentration of alcohol. The machine is set to assume that everybody’s breath temperature is 34 degrees Celcius, and is calibrated at that level. Problem is, 34 C is not even the average breath temperature. A more medically and scientifically supported breath temperature is 35 degrees Celsius. Some people will be higher, and some lower. Every 1 degree Celsius of elevation of body temperature will mean about a 6.7% increase in the breath test result. That error is built into this machine! God forbid anyone should have a fever or an elevated body temperature due to fear and nervousness. Also, when a police officer tells someone to take a deep breath and “hold it” before blowing into the machine, the breath temperature is heated up which causes a higher breath test result (the body is 37 degrees Celsius).
This barely scratches the surface. I could go on all day and night about the unreliability of the Intoxilzer, but almost no one likes science. There is a better way to test breath, that other states have gone to. A company called Draeger makes a machine that 1. takes the temperature of the driver’s breath and adjusts accordingly, 2. takes 2 different kind of measurements of the breath each time (fuel cell and infared), and 3. requires 2 tests of the person’s breath so they can be compared for precision and accuracy. Of course, this machine costs a little more and requires a little more of the person operating the machine. My question is, though, isn’t good science and good justice worth it?