Continued from page 3...
How does all this interpret into everyday experience? An average DUI suspect of 150 to 170 pounds probably must consume, on an empty stomach, approximately 8 to 10 ounces of 100 proof whiskey (8 to 10 beers or 4 to 5 highballs) to reach a blood-alcohol level of .15 percent; this is equal to 15 parts of alcohol per 10,000 parts of blood in the subject's system by weight, or about 2 parts of alcohol by volume for every 1,000 parts of blood. But, again, the ever-present aspect of individuality can confound scientific premises. A heavy drinker, because of his altered physiology or biochemical reactions, may have to drink 12 ounces of 100 proof whiskey before that same level of .15 percent is reached. And a level of .15 percent can have wildly different effects on the nervous systems of different drunk driving suspects in a California DUI case and hence on their ability to operate motor vehicles safely.
All of this is, of course, theoretical. The one simple overriding fact that continues to frustrate attempts to measure blood-alcohol concentration in California DUI investigations is the incredible variability between one individual and another - and, within a single individual, from one moment to the next.
Dr. Kurt Dubowski, probably the most recognized expert in the field of blood-alcohol analysis, has succinctly summarized some of the problems with DUI blood-alcohol tests in an article entitled Absorption, Distribution and Elimination of Alcohol, 10 Journal of Studies on Alcohol Supp. 98 (1985):
First, not all blood and breath alcohol curves follow the Widmark pattern, nor is the elimination phase linear. Second, alcohol absorption is not always complete within 60 to 90 minutes as often claimed. Third, the peak alcohol concentration cannot be validly predicted or established in an individual instance without frequent and timely measurement of alcohol concentrations. Fourth, it is not possible to establish whether an individual is in the absorption or elimination phase, or to establish the mean overall rate of alcohol elimination from the blood or breath, from the results of two consecutive blood or breath alcohol measurements, however timed. Fifth, significantly large short-term fluctuations occur in some subjects and result in marked positive and negative departures from the alcohol concentration trend line. Sixth, short-term marked oscillation of the blood or breath alcohol concentration can occur at various points on the curve, resulting in repeated excursions of the alcohol concentration above and below a given concentration within a few minutes or for hours. Finally, no forensically valid forward or backward extrapolation of blood or breath alcohol concentrations is ordinarily possible in a given subject and occasion solely on the basis of time and individual analysis results.
<< Previous | Page 4 of 4 | Next >>