Challenging DUI Breath Testing: The Timing of the Pretest Deprivation Period
Arizona law enforcement often uses breath-testing devices to determine the blood-alcohol concentration (BAC) of a person suspected of DUI. The Intoxilyzer 8000 is commonly used in Maricopa County. When a person is suspected of DUI, he is generally requested to blow twice into an Intoxilyzer; this is referred to as “duplicate breath testing.”
The Department of Public Safety (DPS) has issued regulations for duplicate breath testing, which it defines as “two consecutive breath tests that immediately follow a deprivation period, agree within 0.020…of each other...”
In addition, the Department of Public Safety defines a deprivation period as “at least a 15-minute period immediately prior to a duplicate breath test during which period the subject has not ingested any alcoholic beverage or other fluids, eaten, vomited, smoked or placed any foreign object in the mouth.” Breath-testing experts have stated that the deprivation period is critical to the breath-testing process. (See Kurt Dubowski, “Quality Assurance in Breath-Alcohol Analysis,” Journal of Analytical Toxicology, Vol. 18, October 1994.)
All DUI convictions in Arizona now require an ignition interlock device for at least a year. Practically speaking, this means that a person will be forced to “blow” into the device to show there is no alcohol in his or her system every time he or she starts a car, and approximately every 15 to 30 minutes while the vehicle is operating.
Law enforcement's primary method for determining if a person is driving under the influence of alcohol is a chemical test. That is, a police officer will take a sample of a susect's blood or breath. The chemical test assumes that the composition of everyone's blood is the same. Specifically, the test assumes that all people have the same hematocrit level. However, this assumption is incorrect.
Over a century ago, the Indiana Supreme Court in Webb v. Baird, 6 Ind. 13 (1853) , formally recognized the right to an attorney for a person accused of a crime. However, the court did not base its decision on constitutional law. Rather, it determined this right was grounded in "the principles of a civilized society."
Field sobriety tests are any one of several roadside tests that can be used to determine whether a suspect is impaired. These psychophysical tests are performed on DUI suspects to assist an officer in the decision to make an arrest. In theory, these tests directly assess impairment by focusing precisely on the human capabilities needed for safe driving. 