Scientific Arguments in DUI Cases

At first blush, a DUI investigation and case would see fairly straight forward: was the driver impaired by alcohol or drugs while driving their car? Although they seem simple, DUI cases are unique in that they present a number of complex legal, factual and scientific issues.scientific-defense-arguments-in-dui-cases

The Scientific issues in a DUI case depend on the scientific evidence gathered by police:

The scientific evidence against a driver in a DUI case starts at the first police encounter with the driver. Officer observations of the driver’s eyes, demeanor and coordination are the first clues of impairment. Next comes the Field Sobriety Tests: tests of dubious scientific validity and done under less than ideal conditions. Next comes the blood or breath testing, which is what most people think of when they think of a DUI investigation.

Officer observations of the driver:

In every DUI investigation, a law enforcement officer has an encounter with the driver. Often this is done at the side of the road, through the driver’s window as the officer first makes contact with the driver. The officer is trained to look for signs of impairment in the driver: red watery eyes, slurred speaking, the smell of an alcoholic beverage and similar cues.
In court, prosecutors are often giddy that the officer can testify about seeing these conditions and hold a near gospel respect for the “signs of impairment.” This respect is misplaced: The officer’s memory is often faulty, and many of the conditions observed by the officer have innocent explanations. For example, red watery eyes are a common condition for people suffering from allergies. Slurred or stuttered speaking can just as easily be explained by a nervous driver who has never been arrested before becoming frightened by the officer’s conduct.

Field Sobriety Tests: The bogus science of field “exercises” for DUI cases.

The National Highway Traffic Safety Administration (NHTSA) has developed a series of “field sobriety tests” that are really no more than silly parlor trick exercises that are used by law enforcement to trick and entrap drivers into performing ridiculous tests that are designed for failure.
After a detailed explanation to a jury, most jury members realize the Field Sobriety tests are nothing more than contrived exercises used to make a normal person look impaired. Most jurors, after carefully reviewing the evidence, give the FST’s little weight in court.

For more information on scientific defenses to DUI cases, check out this site: Colorado DUI Lawyer.

Difficulties with certain defense strategies

The rising BAC defense can be very effective, however juries can sometimes be swayed to ignore the science and convict a driver even in cases with a strong rising Bac defense. Why? The most common reason is an oversimplified view on DUI cases that goes like this: many people feel that if a person drinks alcohol, then gets behind the wheel, they are guilty of something. This viewis simple to understand and those peope that hold this view feel that they are doing justice by holding drunk drivers accountable in the most basic way.

The problem with this oversimplification is it punishes behavior that is not a criminal act. If everyone who had a drink and then drove a car was automatically guilty of a crime, every person who had a glass of wine with dinner at Olive Garden would be a criminal. That outcome is absurd, because those folks do not have a BAC above 0.08% while they were driving. Using the same standad (which is the law) a person on trial for DUI should not be convicted for DUI unless the prosecution can prove beyond a reasonable doubt the driver’s BAC was above 0.08%. In cases with a rising BAC defense, the proseation cannot show this and therefore the jury should acquit.


Posted in DUI Attorney, DUI Defenses.

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