Wednesday, May 16, 2007

In Answer to a commenter's question Below . . .

Here is an article about how to fail a field sobriety test - the truth is, it is not that hard. My reading of the article is that under absolutely optimal conditions, field sobriety tests are wrong almost a third of the time, that under less than optimal conditions, they are wrong 46% of the time, and that ". . . field sobriety tests are irrelevant and, in fact, designed for failure."

Here is an excerpt, but read the whole thing:

Roadside field sobriety tests (“FSTs”) are commonly used by police officers in DUI investigations to determine whether a driver is under the influence of alcohol. Typically, they consist of a battery of 3-5 excercises, such as walk-and turn, one-leg stand, “nystagmus” (“follow the pencil with your eyes”), finger-to-nose, alphabet recitation, “Rohmberg” (eyes-closed-position-of-attention), etc. The officer may subjectively decide whether the individual “failed”, or he may decide after applying recent federal “standardized” scoring.

These DUI tests have an aura of scientific credibility. Unfortunately, however, they have no real basis in science and are almost useless in a drunk driving case. First, as any traffic officer or DUI attorney knows, the decision to arrest is made at the driver’s window; the FSTs given supposedly to determine probable cause to arrest are actually for the purpose of gathering evidence. Second, since the officer has already made up his mind, his subjective decision as to whether a person passed or failed field sobriety tests is suspect: as with any human, he will “see” what he expects to see. Third, the conditions under which the field sboriety tests are taken almost guarantee failure: usually late at night, possibly cold, along a graveled or sloped roadside, with bright headlights from passing cars (setting up wind waves), the officer’s flashlight and patrol car’s strobe and headlights providing the lighting — and given to a person who is nervous, frightened and completely unfamiliar with the tests.

The tests are crap, but so is the breathalyzer (hint, don't eat bread, smoke, or make the officer angry enough to shake the field breathalyzer, don't diet, paint, or deal with other chemicals containing acetone). Heck, even the ones at the station are based on physiological norms, not on an individual's actual alcohol level.***

On another note, I do seem to be seeing this a lot. MADD volunteer gets DUI.

That's probably because 0.08 is too low a threshhold.

Kid H.

*** The machine measures alcohol on the breath, and an internal computer then multiplies the reading 2100 times to get a reading of alcohol in the blood. This is because the amount of alcohol in the blood is greatly reduced as it crosses from the blood into the alveolar sacs of the lungs and into the breath; the average person has 2100 times more alcohol in his blood than in his breath (this varies widely among individuals, however, and is another inherent defect in the machines).


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