Alcohol Absorption, Distribution, and Elimination

In California DUI / DWI cases, evidence about the driver's blood alcohol content (BAC) can the most damning - or the most vindicating - evidence in court. To see why, it's useful to understand how the body absorbs, distributes, and eliminates alcohol, and how a driver's BAC is affected. The skilled DUI / DWI criminal defense lawyers at The Kavinoky Law Firm are well-versed in the science of alcohol metabolism and will use this information to challenge chemical test results and help a motorist fight a drunk driving case.

DUI / DWI prosecutors regard a driver's chemical test results as one of the most important pieces of evidence in a California driving under the influence case. However, everyone metabolizes alcohol differently, so it is extremely difficult to look backward in time to accurately pinpoint BAC when the driver was behind the wheel. This difficulty increases with the passage of time, and becomes increasingly speculative.

In addition, the integrity of a blood test hinges on whether the sample was properly collected, stored, and tested. Clearly, for the DUI / DWI criminal defense attorney whose expertise lies in highlighting reasonable doubt as to any element of the criminal case, this becomes increasingly valuable.

When an individual takes a drink of alcohol, it isn't absorbed into the body right away. It first enters the stomach, then the small intestine, where most of the absorption takes place. How fast the alcohol is absorbed depends on the type of drink consumed, the individual's stomach contents, and many other factors.

The body starts eliminating alcohol immediately, but cannot dispose of it at the same speed at which it is absorbed. This is how an individual's BAC rises - the body is like a bathtub with a slow drain. The water flows in faster than it flows out, so the level increases. Alcohol absorption in the human body occurs in much the same way.

The body continues to absorb alcohol even after an individual stops drinking, and the BAC continues to rise until it reaches a plateau. This peak represents perfect equilibrium - absorption and elimination of alcohol is occurring at the same rate, so the alcohol level flattens out and is consistent for a period of time. This plateau typically lasts for 15 to 45 minutes, depending upon stomach contents and metabolic rate.

After the body's blood alcohol content plateaus, the elimination phase begins. If the individual stops drinking, the BAC will steadily decrease at an average rate of approximately .02 percent per hour - about the equivalent of one drink. This, too, varies widely from person to person and in situation to situation.

The process of alcohol metabolism is represented graphically like a bell curve. Because a driver's BAC continues to rise after he or she stops drinking, a chemical test that shows that the driver was above the legal limit of .08 percent BAC doesn't mean the motorist was intoxicated while behind the wheel.

Many experts agree that breath-testing during the absorptive phase - after a driver stops drinking, but before alcohol content peaks - can overestimate true alcohol levels by 40 percent to 100 percent.

Many factors can affect the results of a chemical test in a driving under the influence investigation, including the motorist's metabolic rate, stomach contents, and fatigue level. Often, an officer's roadside investigation doesn't even begin to address these issues. A skilled California DUI / DWI criminal defense lawyer can devastate the prosecution in a drunk driving case during an effective cross-examination.