“Trial by Machine”….But How Good Are the Machines?

Posted by Lawrence Taylor on February 15th, 2009

All states now have two drunk driving laws: (1) driving under the influence of alcohol (aka “DUI”, with local variations, such as “driving while intoxicated” or “DWI”), and (2) the so-called per se law of driving with .08% or higher blood-alcohol concentration (BAC). Unless you refuse to take a chemical test, you will be charged and prosecuted for both offenses — and can be convicted of both.

The breath machines (commonly — and inaccurately — referred to as “Breathalyzers”) used to obtain the BAC are, obviously, critical to the drunk driving case. As for the per se offense, the only evidence of the crime is the machine: if the thing says .08% or higher and the jury believes it, the defendant is guilty.  In effect, if you are accused of driving with .08% BAC, you will face "trial by machine" — and you will not be able to confront your accuser.

It gets worse….Even as to the DUI charge, the readings will be considered presumptive: if the BAC is .08% or higher, the jury will be instructed by the judge that the defendant is presumed to be guilty — and he must be found guilty unless he can prove his innocence.  See “Whatever Happened to the Presumption of Innocence?”.

These machines are all-important: they determine guilt or innocence. But despite the manufacturers refusing court orders to disclose the software that runs the machines (see What Are Breathalyzer Manufacturers Hiding?), they continue to assure us that the things are “state of the art”.  So how accurate are they?

Well, as I’ve written in the past, not very.  Just a few examples:

Breathalyzers — and Why They Don’t Work
Close Enough for Government Work
The Mouth Alcohol Problem
Breathalyzers: Why Aren’t They Warranted to Measure Alcohol?
Driving Under the Influence of….Bread?
Warning: Breathalyzer in Use
Breath Fresheners and Breathalyzers
Diabetes and the Counterfeit DUI
Why Breathalyzers Don’t Measure Alcohol
Can Body Temperature Affect Breathalyzer Results?
The Effect of Anemia of Breath Tests
GERD, Acid Reflux and False Breathalyzer Results
Driving Under the Influence of….Gasoline?
Do Breathalyzers Discriminate Against Women?
Breathalyzer Inaccuracy: Testing During the Absorptive State
Breathalyzer Inaccuracy: Post-Absorptive
Breathalyzer Inaccuracy….It Gets Worse
Warning: Smoking Can be Hazardous to Breathalyzer Results
How to Fool the Breathalyzer
Breathalyzer Manufacturers Won’t Tell How They Work

State of the art? Far from it, yet thousands of American citizens continue to be accused and convicted by these machines…..