Saturday, April 5, 2008

Margin of Error for California DUI Breath Test Machines

California DUI attorney information

In California, it is a criminal offense to drive with .08% alcohol in your blood. A number of people suspected of violating that law are given California DUI breath tests to determine their blood-alcohol concentration (BAC). The California DUI breathalyzer will take a small sample of the California DUI suspect’s breath and estimate how much alcohol is in it. Based on that, the Government estimates how much alcohol may be in the blood. According to The Government, what the California DUI machine says is pretty much the end of the story. They usually do not allow any second set of California DUI tests. The Government allows no cross-examination of the California DUI machine.

Are these California DUI machines so reliable and accurate that Californians have permitted them to become judge and jury? The Government says they can.

California DUI forensic toxicologists universally recognize an inherent error in breath analysis, generally of (at least) plus or minus .01%. That means that if everything about the California DUI machine is working perfectly (an unlikely scenario), a .13% breathalyzer test result can be anywhere from .12% to .14%. This has been acknowledged by DUI courts across the country (in California, People v. Campos, 138 Cal.Rptr. 366; in Alaska, Haynes v. Department of Public Safety, 865 P.2d 753; and in Hawaii, State v. Boehmer, 613 P.2d 916, recognizing an even larger - .165% inherent error).

The Government says these machines are accurate but what do these range of errors say about the real accuracy of these California DUI breathalyzers? Suppose, a California DUI test result appears to be .10%. Considering inherent error into consideration — and assuming the California DUI machine was working perfectly, the California DUI officer administers the test correctly, and the California DUI suspect’s health/fitness/physiology is normal and perfectly average — the true California DUI BAC could be anywhere from .09% to .11%. So based on that, the true BAC can be 10% in either direction — or anywhere within a 20% total margin of error for the California DUI machine.

California DUI machines have a 20% margin of error, meaning a California DUI person accused of driving with over .08% BAC can be convicted by a machine which, if everything else is perfect, has a built-in 20% margin of error. Would you be comfortable with a brain surgeon who worked with a 20% range of error? A pilot? An accountant? What about the evidence in a California DUI criminal case where guilt must be proven beyond a reasonable doubt? Good enough for The Government, Our Government, Your Government. No wonder some California DUI lawyers make it a career trying to defend the Innocent & Worthy!