Driving Under the Influence and Alcohol Absorption

We often hear the terms “BAC”, “Blood Alcohol Content” or “Blood Alcohol Level” when we are reading the news or listening to criminal defense attorneys speak on television about DUI arrests or serious car accidents, but what does BAC really mean? The level of alcohol in a person’s body can be measured by either a blood or breath test.

Over the years, breath measuring devices, such as the Datamaster, have become the more popular choice for law enforcement. A test of .08, or eight-hundredths of one gram or more by weight of alcohol per one hundred milliliters of blood or eight-hundredths of one gram or more by weight of alcohol per two hundred ten liters of breath, is the typical beginning threshold for a DUI offense in most jurisdictions.

The question again then is what does .08 mean? To answer this question we need to briefly discuss how alcohol absorbs into the body. Typically alcohol is taken in by the mouth. When the alcohol is ingested, some of the alcohol is absorbed by the membranes in the mouth; however, most of the alcohol goes down the esophagus and into the stomach. Alcohol is then absorbed in the duodenum or small intestine. Eventually, the alcohol makes its way into the general circulation. When we feel the effects of alcohol, or feelings of drunkenness, it is because the alcohol is circulating throughout our body and affecting our brain.

Alcohol absorbs into the body at roughly .02 per drink. A “drink” is defined as one ounce of 80 proof alcohol, one regular 12 ounce beer at roughly 5 percent alcohol or four ounces of unfortified wine. Therefore, it comes as no surprise that a person will begin to feel the effects of alcohol sooner when drinking hard liquor versus light beer.

It takes about 30 to 60 minutes for alcohol to fully absorb after it has been ingested, and there are also other factors that affect how fast the alcohol absorbs, including a person’s size and whether that person is drinking on a full or empty stomach. So if a person of average size is drinking regular twelve ounce cans of Bud Light on an empty stomach, we can estimate that if that person has three or four beers within an hour time frame, their blood alcohol level will likely be close to.08. Now, we must also account for the fact that the body is eliminating the alcohol as it is absorbed. This is why it is often said that as long as a person keeps within one to two regular drinks per hour, their blood alcohol level should remain below.08. With that said, even a small amount of alcohol in your system can result in impairment and slower reflexes, and many car accident injury claims occur because someone was driving while impaired. It is always best to avoid getting behind the wheel after consuming any alcohol.