Breathalyzers Fail Legitimacy Test
The Breathalyzer test is the technological backbone of the nation's anti-drinking and driving laws. This is the process where the breath of suspected drunk drivers is tested for the presence of alcohol. The Breath alcohol content is then converted by a standardized formula to determine the Blood alcohol content, which is the actual indicator of impairment.
Many officers in the field rely on breath alcohol testing devices (Breathalyzer is one type) to determine the blood alcohol concentration (BAC) in drunken-driving suspects. While the Breathalyzer test appears to be scientific, equitable, and fair, it is actually none of these things. It is not scientific nor does it rely on existing and accepted science. It is not equitable because there is a wide margin of variation in the results from person to person. People who are not realistically impaired have been found "guilty" of drunk driving and other people who may be significantly impaired have avoided detection.
Blood alcohol content can be accurately measured by a blood test. Blood alcohol content has been generally accepted as an accurate indicator of impairment. Setting aside the accepted fact that alcohol tolerance and effect varies greatly from individual to individual, lets focus a moment solely on the ability of the breathalyzer to accurately determine Blood alcohol content by measuring Breath alcohol content.
Peer reviewed and uncontested studies (LaBianca, Simpson, Thompson et.al.) prove a margin of error of 50 % when comparing breathalyzer estimates of Blood alcohol content to actual Blood alcohol content! That means a breathalyzer reading of .1 % represents a Blood alcohol content level somewhere between .05 % and .15%, hardly a level of precision on which to base an irrefutable presumption of guilt!
When confronted with this proven inability of breathalyzers to accurately represent Blood alcohol content some state legislatures, in their wisdom and desire for expedience, have decided to grant Breath alcohol content the same status as Blood alcohol content as irrefutable evidence of intoxication, impairment and drunk driving. This is criminal in its error and implementation. Breath alcohol content is a legitimate measurement of only one thing, the alcohol content of the sample of air it is measuring. It is not an accurate indicator of Blood alcohol content, nor an accurate indicator of alcohol related impairment.
Breathalyzer readings should not be considered as per se evidence of Driving While Intoxicated (or impaired) unless the reading is high enough to overcome the inherent 50 % margin of error. That means a Breathalyzer reading must exceed .2 % in a state with a .1 % DWI threshold to be granted per se status (irrefutable presumption of guilt). Breathalyzer readings above .1 % and below .2 % should be accorded prima facie status (rebuttable presumption of guilt). Breathalyzer readings below .1 % should be accorded no credibility beyond providing probable cause for a DWI arrest. In no case should breath alcohol content be considered an accurate measurement of Blood alcohol content or the degree of impairment.
The desire to eradicate the deaths, injuries and property damage associated with drunk driving does not excuse the courts or legislatures from their duty to provide just laws that are fairly administered. If standards, limits and quantities are included in these laws they should be relevant to the subject at hand, clearly delineated, and accurately measured. If there is room for substantial error there should be appropriate opportunities for the accused to address those errors in their defense. The "rush" to arrest and punish drunk drivers has badly trampled these principles.
Why Breathalyzers Don’t Measure Alcohol
Breathalyzers don’t actually measure alcohol. What they actually detect and measure is any chemical compund that contains the methyl group in its molecular structure. There are thousands of such compounds — including quite a few which can be found on the human breath. And this machine that determines a person’s guilt or innocence will “see” all of those chemicals as alcohol — and report a falsely high “blood-alcohol” concentration (BAC).
The Flawed Nature Of Breath-Alcohol Analysis
Breath-alcohol analyzers used by law enforcement agencies to evaluate suspected driving-while-intoxicated (DWI) drivers are routinely calibrated with standard, dilute aqueous solutions of ethanol known as simulator solutions. The analyzers are deemed accurate if they generate results within an established margin of error consistent with ethanol concentrations equivalent to the actual concentrations of the simulator solutions.
The fundamental flaw of this protocol is that it ignores the fact that a simulator solution is an ideal Henry's law system, whereas a human test subject is not. Since breath-alcohol analysis is an application of Henry's law, the level of accuracy ascribed to simulator-based calibrations cannot be applied to analyses involving humans because they are affected by physiological variables that can significantly impact the results of such analyses.