Breathalyzers Fail Legitimacy Test
Little known and seldom publicized is the fact that breathalyzers may err as much as 50% in determining actual blood alcohol content
August, 1999A note from our friends at the National Motorists Association, one of the few national organizations that consistently stands between beer lovers and those who continue to demonize all drinkers because of the irresponsible actions of a few.
The technological backbone of the nation's anti-drinking and driving laws is the Breathalyzer test. This is the process where the breath of a suspected drunk driver is tested for the presence of alcohol. The Breath alcohol content is then converted by a standardized formula to estimate the Blood alcohol content, which is the actual indicator of impairment. Little known and seldom publicized is the fact that Breathalyzers may err as much as 50 percent in determining actual Blood 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 irrebuttable presumption of guilt!
When confronted with this proven inability of breathalyzers to accurately represent Blood alcohol content, certain state legislatures have decided to grant Breath alcohol content the same status as blood alcohol content as irrebuttable evidence of intoxication, impairment and drunk driving. 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.
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.
Breathalyzer readings should not be considered as per se (absolute, irrebuttable) 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 (irrebuttable 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 National Motorists Association was established in 1982 to represent the interests and rights of North American motorists. It operates at the national level and through a system of state chapters. The NMA is solely supported through the contributions of individuals, families and small businesses. For more information about the NMA, call 800-882-2785, fax us at 608-849-8697, E-mail us at nma@motorists.org or visit the NMA web site at http://www.motorists.org.
