June 28, 2013

In the United States, a DUI is considered a very serious offense. In 1980th, approximately 25,000 people died in DUI accidents per year. Since then, the states put a lot of effort into prosecuting DUI drivers. By 2014, the number of death from DUI-related accidents dropped to just below 10,000 people per year. While this is still a large number, the tough stance on DUI offenses appears to be paying off. The total number of people arrested for drunk driving in the United States is over 1 million arrests per year.  The prosecution all over the United States and California is extremely tough on DUI cases, often prosecuting borderline cases – that is, cases that if not a DUI, would not be filed. Because of that, if you are arrested for a DUI in Los Angeles, you might be innocent despite being over the legal limit of .08% BAC. The answer lies in the way the human body works which explains why someone who is tested over the legal limit at the time of driving might not be guilty of a DUI. While many factors can influence blood alcohol levels, one of the basics is known as the metabolism of alcohol, to wit, how alcohol gets processed by a human body from consumption to excretion. Once alcohol is consumed, it will get absorbed by the body over a period of time lasting up to 6 hours or even more. Once fully absorbed, the level of alcohol in the body will stay constant for a period of time. After that, the alcohol will get eliminated from the human body at a usually constant rate until the BAC reaches 0.

Because the results of alcohol tests are not reliable when the body is absorbing alcohol, one of the best ways to defend a DUI case is to argue inaccurate results of a blood test in the absorption phase.

What is known as the DUI absorption rate is a rate of alcohol metabolism that will change as time goes by and as the person stops drinking.


This is a common issue at trial for a DUI in Los Angeles because it takes time for a person arrested for a DUI in Los Angeles to get to the highest level of alcohol in his blood. Once the highest level of alcohol is known, DUI experts can be estimated the level of alcohol at the time of driving, when that person will be sober, and when that person was at .08 percent BAC. However, all the calculations are based on an approximate level of elimination by an average individual, at around .015 to .02% per hour.

Because testing of blood or breath occurs sometimes after driving – and the crime has to do with being above the limit at the time of driving, Los Angeles DUI prosecutors have to call experts to testify as to the BAC level at the time of driving. The prosecutor will try to prove that you were above the legal limit of .08% BAC at the time of driving and thus guilty of a DUI in Los Angeles. The expert prosecutorial witness will testify by making educated guesses as to what was blood alcohol concentration (BAC) a the time of driving by looking at the time passed since driving, knowing how much alcohol was consumed, and the level of alcohol at the time of testing. This technique is called “retrograde extrapolation” and it is very inaccurate. The reason it is inaccurate is the expert’s necessity to make assumptions about the driver that is based on averaging all people together. For example, government experts will usually assume that all people are “fully absorbed” 30 minutes after drinking.  However, this assumption was proven wrong and other scientific research shows that absorption can last 60 minutes and up to 6 hours.  For example, Goldfrank’s Toxicologic Emergencies Treatise, which is a book commonly used to study alcohol impairment by doctors and other health science professionals states that “80% to 90% of ingested dosage is fully absorbed within 60 minutes when conditions are optimal”.  But often conditions are not optimal and a great many things affect absorption. Some experts concluded in their research that alcohol does not absorb until food leaves the stomach, which is why the absorption rate slows to up to 6 hours or more.


  1. Presence of food in the stomach – When a person consumes food, it slows down the rate of absorption. A person who does not have any food will get drunk quicker on empty stomach. A typical rate of absorption of 30 minutes on an empty stomach will slow down to hours because of a recent meal.  This is due to food in the stomach interfering with the absorption of alcohol. For example, British Medical Journal found that even on an empty stomach it takes nearly 5 hours for food to leave the stomach.
  2. How fast the stomach empties – is a physiological factor that can’t be predicted by government experts. The rate of elimination is dependent on many physiological factors including the rate of elimination. If a person’s stomach will empty slow, it will slow down the process of absorption.
  3. The level of alcohol in the alcoholic drink. Research has shown that alcohol absorbs the quickest when the alcoholic drink has an alcohol concentration of nearly 20%. If the alcoholic beverage’s alcohol concentration is lowered by 20%, the alcohol will be absorbed much slower. The opposite can also be true, a high alcohol concentration may not increase absorption because high alcohol concentration can irritate the stomach lining and reduce the absorption rate.
  4. Carbonation of an Alcoholic Drink – Carbonated drinks will reduce the level of absorption. If you consumed champagne or consumed a hard liquor drink with added soda, the level of alcohol absorption will change and it would be once again hard to calculate the level of absorption without knowing.
  5. Medications will affect the level of absorption. For example, even taking such common medication as aspirin might change the level of alcohol absorption and even elimination and will make the calculation of impairment much more difficult.
  6. Rate of Consumption: One of the most important factors affecting absorption is the rate at which an individual consumes alcohol. For example, a slow drinker will absorb alcohol at a much slower rate than a fast drinker. Someone who sips his drink throughout the day clearly will not get as impaired as a person who gulps his drink quickly.
  7. Medical conditions will often affect the rate of absorption and elimination. For example, stomach conditions and conditions related to gastrointestinal illnesses (such as GERD) might have a huge impact on the level of absorption and elimination and will make the calculation of impairment very difficult. Additionally, GERD will cause alcohol to be expelled back into the esophagus, which will influence the breathalyzer machine, giving you a falsely high BAC reading.
  8. Individual variations of each person can play a significant role in the absorption and elimination of alcohol. Each of us is a different person who does not fit a prosecutorial model of an average person. For instance, an average man in the United States is 5’10, but most people you know are not.
  9. Presence of body fat: Recent article concluded that women with obesity clear alcohol from their system 52% slower than non-obese women. The same applies to even small variations in body fat composition. The research article was published in Alcohol Clinical and Experimental Research by a group led by M. Yanina Pepino, a professor of food science and human nutrition at the University of Illinois Urbana-Champaign. The study focused on women and used 143 women from various age groups and different levels of body fat. The average alcohol elimination rates were 6 grams per hour for the healthy weight group, 7 grams for the overweight group, and 9 grams for the group with obesity,” she said. “To put this in perspective, one standard drink is 14 grams of pure alcohol, which is found in 12 ounces of beer, 5 ounces of table wine or 1.5 ounces shot of distilled spirits.” However, we expect that similar research with male subjects will produce similar outcomes with the level of elimination different depending on the level of body fat.
  10. With so many factors affecting absorption/elimination – it is clear that many government experts are not intellectually honest when they provide testimony that absorption/elimination is identical among all people. Los Angeles DUI attorney has the necessary experience to defend you against the government and the experts who will say almost anything to secure a conviction. Through a process called “impeachment”, a Los Angeles DUI attorney can show the errors in experts’ calculations and the wrong assumptions made by the prosecutors. Los Angeles DUI defense attorneys will cross-examine DUI prosecutor’s experts and will expose the truth and show how inaccurate their testimony is and ultimately that the government can not prove beyond a reasonable doubt that you were above the legal limit when you drove the car.


A common theme during a DUI trial is the speed with which alcohol gets absorbed by the body.  Assuming a driver stopped drinking at some specific time, the alcohol level will rise until some point later and will eventually reach a constant level (aka plateau).  The speed of absorption matters because during the absorption phase, a person’s breath results are overestimated giving the appearance that the person’s blood alcohol level is higher than it really is.  The overestimation can be as high as 40%, which means that a .07 BAC would be measured to be .10 BAC. Also, the speed of absorption is very important to determine the blood alcohol level at the time of driving.  Since expert toxicologists can’t agree what was the speed of absorption with which the defendant’s body absorbed alcohol, the level of alcohol at the time of driving cannot be determined.   Common research material indicates that under optimal conditions consumed alcohol will be fully absorbed by the body within 30 to 60 minutes.   Yet, optimal conditions are not that common in real life.  For example, alcohol best absorbed when its concentration is at .20%.  Dilution will cause slow absorption, thus beers will not be absorbed within 30-60 minutes but for longer periods of time. Similarly, hard liquor will be absorbed slower because its higher alcohol level will cause irritation and spasms inside the digestive tracks and it will delay absorption.  When these and other factors are present, the absorption can be delayed by 2 to 6 hours.  Therefore, the prosecution’s expert opinions that “all alcohol is absorbed within one hour”  need to be taken with a grain of salt if only because the burden of proof in a criminal case is exceptionally high.


During the absorption, the results of the breath test will overestimate the results of a true alcohol level in the body by at least 40% (and some literature shows by as much as a factor of 3). This is so because the breath alcohol results come from the lungs, which are supplied by arterial blood. Venous blood is a better measure of BAC, however, there is no way to measure venous BAC through breath. The simplest way is to wait until sufficient time passes for elimination to start.

In science, a University of Zurich study showed results of 2 times as high in arterial blood than in venous blood at the time of absorption. Thus, breath testing is not a reliable means of estimating a subject ABC during absorption.

Real-life application: A client was charged with a DUI after he tested .09% BAC one hour after stopping drinking.  He admitted to drinking several beers.  Beers have a slow absorption rate, therefore he should be absorbing alcohol at the time of the test; thus, at the time of driving his blood alcohol level must be below the legal limit. However, this client was charged with a DUI in Los Angeles and it took a lot of effort by the Los Angeles DUI Attorney to convince the prosecutor to dismiss your DUI. If you are looking to have a professional help you defend your DUI in Los Angeles, call our office anytime.

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