Blood Alcohol Science: Preparing a DUI Defense

California DUI Laws criminalize driving under the influence of alcohol and/or drugs because a driver’s ability to safely operate a motor vehicle is impaired. Blood-Alcohol studies have clearly demonstrated that a driver’s ability to perform divided-attention tasks (i.e. stopping in time, changing lanes safely, managing speed, being aware of traffic around him) is substantially affected by drugs and alcohol.

When an alcoholic beverage is consumed, the alcohol is absorbed into the blood stream through a process called diffusion, and the alcohol is then delivered to the tissues and throughout the water-containing portions of the body as part of the process of distribution. Billions of nerve cells called neurons compose the brain, and each neuron has three parts: the cell body, the dendrites and the axon.  Alcohol interacts with proteins found in the cell membranes, specifically those involved in neurotransmission, or those that carry messages to and from the brain.  Alcohol both inhibits and stimulates neurotransmission – which causes a driver to poorly perform divided attention tasks.

One of the ways law enforcement officials and agencies determine whether or not an individual is impaired to operate a vehicle safely (Driving Under the Influence - DUI) is through his or her blood-alcohol concentration. Because blood-alcohol science is complex, law enforcement’s attempts to establish a driver’s blood alcohol level, hours after an arrest, may end up in a flawed investigation and inaccurate police reports. The following discussion addresses relevant factors in determining if a driver was actually intoxicated at the time of driving, rather than when he or she was at the police station.

Alcohol consumption has varying effects on different people.  These factors are rarely taken into consideration during a DUI stop by police officers, and should be considered by a Los Angeles DUI attorney in formulating a courtroom strategy. Importantly, if the prosecution cannot demonstrate you were intoxicated at the time of driving beyond a reasonable doubt, then a jury would find that you are Not Guilty of the DUI charges.

Absorption:  Was the alcohol fully absorbed in your blood at the time of driving? Alcohol is absorbed from all parts of the intestinal tract, largely by simple diffusion into the blood.  The small intestine however is by far the most efficient region of the intestines for absorption because of its large surface area.

Distribution: Was the alcohol distributed? An individual's body strives for equilibrium. When alcohol enters the body and absorption is complete, equilibrium occurs as the body transfers the alcohol equally throughout the tissue in the person's body until there is a complete balance.  The timing of the distribution process plays a role in your blood alcohol concentration at time of the traffic stop by law enforcement.

Elimination: Was the alcohol eliminated from your blood stream? The liver is the body's main organ in dealing with the elimination of poisons, alcohol and other substances.  This happens through metabolism, which handles 95% of ingested alcohol from the body.  Healthy people, with a healthy metabolism, can eliminate alcohol efficiently. However the rate of elimination tends to be higher when the blood alcohol concentration is very high or very low. 

Body Weight and Body Type: Most likely, the less you weigh, the more you will be affected by a given amount of alcohol.  Your body weight and your body type (fat vs. muscle) has an impact when trying to determine how much alcohol you can consume before you are unable to safely operate a motor vehicle. With more fat, the rate of alcohol absorption is greater.

Rate of Consumption: If most of the alcohol is consumed shortly before a traffic stop, a DUI attorney may successfully argue that you were “on the rise” and not intoxicated at the time of your arrest.

Food: If food is taken along with alcohol, it will result in a lower, more delayed blood alcohol concentration peak, which is the point of the highest intoxication level.  Food can slow the process of absorption of the alcohol and can quicken the process by which alcohol is eliminated.

Medication: DUI charges may be brought, even if a person’s blood alcohol is less than .08%, when a medication or controlled substance is present in the blood stream. Medication can greatly impact the effects of alcohol on a driver’s ability to operate a motor vehicle safely

Fatigue: Fatigue, or being incredibly tired, can mirror or increase the effects of alcohol.

Gender: Obviously, men and women have different body types.  Women tend to have a higher percentage of body fat, and a lower percentage of body water, which would mean that in general, if a man and woman of the same weight ingested the same amount of alcohol, the woman will tend to achieve a higher alcohol concentration because there is less water in her system.

Tolerance: This refers to an individual's ability to endure or resist the effects of alcohol. In terms of DUI charges, someone who regularly drinks may not display outward symptoms of intoxication during Field Sobriety Tests (such as lack of coordination, slurred speech). However, the blood alcohol content is no different whether or not a person has high tolerance levels. Accordingly, someone’s tolerance of alcohol is typically not a complete defense to DUI charges.

These are just some factors related to Blood Alcohol Science that could impact your court defense of DUI charges. There are also relevant environmental factors in the defense of DUI charges. For example, if the police officer's squad car has its siren blaring or its lights flashing, they may impede an individual's ability to concentrate and make him or her appear drunk or intoxicated.

Contact the DUI attorneys at Kestenbaum Eisner & Gorin, LLP to immediately assess your case at 877-781-1570. They are available 24/7.