OTHER DUI/DWI RESOURCES

Breath Test Evidence

Under the Arizona Implied Consent Law, once an individual is arrested for driving under the influence of alcohol, the arresting officer can request the arrestee submit to test or tests of their breath, blood, and/or urine as a means of determine breath or blood alcohol content, provided test or tests occur within two hours of time of driving or time of stop.

In Arizona, the Intoxilyzer 5000 and the Intoxilyzer 8000 are the two devices most commonly used for evidential breath analysis. Both devices are manufactured by CMI in Owensborough, Kentucky. The Intoxilyzer 5000 has been in service and used by law enforcement in the State of Arizona for 20 years. The Intoxilyzer 8000 was first used operationally by South Tucson Police Department approximately three years ago. The Intoxilyzer 8000 is gradually replacing the Intoxilyzer 5000, and has been used by law enforcement in five other states.

The devices attempt to measure breath alcohol content and convert it into a numerical reading or readings equivalent to blood alcohol taken directly from the blood of an individual. (This conversion factor, which is different for each individual, is called a partition ratio). These devices use infrared spectroscopy technology to detect ethyl alcohol molecules in a breath test sample, at particular infrared energy wavelengths in the range of 3.3 to 3.5 microns and, for some devices, at 9.5 microns.

Many other chemicals have wavelengths in these ranges. This means the devices are capable of reading non-alcohol substances as alcohol, which can inflate numerical readings on printer cards for the Intoxilyzer 5000 and Intoxilyzer 8000 artificially, overstating an individual's true BrAC readings on the devices. The device is also subject to electro-magnetic and radio frequency interference (RFI) which may also falsely elevate readings on printer cards.

The Intoxilyzer 8000 is designed as a compact EBT that can be used in either a stationary mode, such as in a police or sheriff's sub-station; or in a mobile mode, as in the back of a police patrol cruiser. Although the device was designed to be a replacement for the Intoxilyzer 5000, and using better technology, and modern CPU/ chips, and software, the I-8000 was withdrawn from service and/or de-certified for law enforcement use in the State of Tennessee in 2005, after the device failed field trials in which the older Intoxilyzer 5000 had more accurate and reliable numerical results than the supposedly new and improved Intoxilyzer 8000.

There are at least fifty (50) potential challenges to breath test results in every case involving breath test results, ranging from officers not following testing protocols for breath tests to medical or health problems such as diabetes that may affect accuracy or breath test results, to environmental exposure to non-alcohol chemicals or interfering substances, such as paint, gasoline, or paint thinners, which may artificially inflate test results on printer cards for the Intoxilyzer; to failure to follow manufacturer's recommended maintenance procedures for the devices; to mouth alcohol getting into the devices, in additional to breath samples, from dentures or reflux of stomach contents into the mouth, getting past mouth pieces and inside the devices; to elevated body temperatures, caused by fever, hot tubs, saunas, hot flashes, and other causes; failures in monthly calibration checks; and other maintenance failures or repairs from the devices.

If breath test results can be precluded or suppressed, and the State is not allowed to use breath test evidence at trial, or if sufficient challenges to breath results can be raised at trial to raise reasonable doubts as to the accuracy and reliability of test results for a particular Intoxilyzer machine in one case, it can make the difference between winning and losing a driving under the influence criminal case for a client.

Source: William C. Head, Esq. Medical-Legal Aspects of Alcohol, Fourth Edition (Lawyers and Judges Publishing Company, Inc., Tucson, Arizona 2003 at pp.373-393).