Rising Blood Alcohol as a DUI Defense Strategy

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Driving under the influence (DUI) charges can have serious consequences, including a possible conviction that may result in hefty fines, license suspension, and even jail time.

However, the use of blood alcohol levels is a defense strategy in DUI cases.

By arguing that their blood alcohol level was rising at the time they were pulled over, defendants may be able to create doubt in the prosecution’s case and potentially avoid a DUI conviction.

Arja Shah is a reputable criminal defense attorney who offers free initial consultations to individuals facing DUI charges. Contact her today to discuss your case and explore possible defense strategies to fight against a DUI conviction.

This article will cover the following topics:

how is alcohol absorbed

How Do BAC Levels Change Over Time 

Blood alcohol concentration (BAC) levels change over time through three main phases: absorption, distribution, and metabolism:

  1. Absorption: Alcohol begins to enter the bloodstream once ingested, with BAC levels rising quickly. The presence of food can slow this absorption, while drinking on an empty stomach speeds it up. For example, a person drinking alcohol after a large meal may exhibit slower BAC elevation compared to someone drinking on an empty stomach.
  2. Distribution: After absorption, alcohol is distributed through body water and reaches its peak concentration. This is when impairment is most noticeable. The peak BAC can vary; for example, it may reach its highest within 30 to 90 minutes after drinking, depending on individual circumstances and the amount consumed.
  3. Metabolism and Elimination: Alcohol is metabolized by enzymes in the liver, primarily alcohol dehydrogenase, which processes alcohol at a consistent rate, typically about 0.015% to 0.020% BAC per hour. This means if a person’s BAC level is 0.08%, it would generally take 4 to 5.3 hours to metabolize the alcohol completely. This rate can be influenced by factors such as liver health, age, and whether the person is a regular drinker.

group of friends drinking together

Factors that Influence BAC Levels 

The level of alcohol concentration in the bloodstream, or BAC, can be influenced by a variety of factors that affect how alcohol is absorbed, distributed, and metabolized.  Here are some of the primary factors:

Biological Factors:

    • Body Weight and Composition: Generally, individuals with higher body weight have a larger volume of blood, which dilutes the alcohol, resulting in a lower BAC. Additionally, fat does not absorb alcohol, so individuals with higher body fat percentages may show higher BACs than those with more muscle.
    • Gender: Women often have higher BACs than men after consuming the same amount of alcohol due to typically having less body water and more body fat per pound. Hormonal fluctuations can also affect metabolism rates.
    • Age: Metabolism slows with age, potentially causing alcohol to stay in the system longer, thus increasing BAC.

Consumption Patterns:

    • Rate of Consumption: Drinking alcohol more quickly will raise the BAC faster, as the body can absorb alcohol much faster than it can metabolize it.
    • Type of Alcohol: Beverages with higher alcohol content, like spirits, can increase BAC more quickly than beer or wine.
    • Food Intake: Consuming alcohol with food, especially high-protein foods, can slow the rate of alcohol absorption, leading to a more gradual increase in BAC.

Metabolic Factors:

    • Enzymatic Activity: Variations in liver enzymes, which metabolize alcohol, can lead to faster or slower alcohol clearance.
    • Overall Health: Liver health significantly affects alcohol metabolism. Conditions like hepatitis or cirrhosis can drastically reduce the rate at which alcohol is processed.

Environmental and Psychological Factors:

    • Stress and Fatigue: Stress and tiredness can alter the rate at which the body processes alcohol, potentially increasing BAC.
    • Medications: Certain medications can interfere with alcohol metabolism, increasing or decreasing BAC unpredictably.

When defending DUI cases, demonstrating how these factors might have influenced the accused’s BAC can be a critical part of the defense strategy, potentially impacting the interpretation of BAC results and the outcome of the case.

breathalyzer test being used to measure bac levels

How is Blood Alcohol Concentration Measured

Blood Alcohol Concentration (BAC) measurements can be conducted through various methods, each with distinct principles and legal implications, especially under stringent DUI laws like those in Arizona (Arizona Revised Statutes §28-1381).


Breathalyzer Tests

Are the most common roadside testing method due to their convenience and non-invasive nature. These devices estimate BAC by measuring the alcohol content in one’s breath. The alcohol in the breath reacts chemically within the device, producing a change in color or an electrical signal that is then converted into a BAC value. However, the accuracy of breathalyzers can be influenced by factors such as device calibration, the presence of substances like mouthwash, and the time elapsed since alcohol consumption.


Blood Tests

Provide the most accurate BAC measurements by directly analyzing a blood sample for its alcohol content. This method is generally utilized in formal settings post-arrest to produce definitive evidence of a person’s BAC level at the time of testing. Despite its precision, the blood test process requires trained medical personnel to draw blood, and strict adherence to the chain of custody and proper sample storage protocols is crucial to maintain the validity of the results.


Urine Tests

Are less frequently used and are considered less reliable than breath and blood tests. These tests measure the alcohol content in urine, which can then be used to estimate the corresponding BAC. The reliability of urine tests can be compromised by factors such as the time alcohol has been in the bladder, potentially leading to higher alcohol readings compared to blood.

Each testing method has its potential sources of error and procedural standards that must be carefully managed.

In DUI defense, attorneys might challenge the results based on procedural errors, the timing of the test, or the calibration and maintenance of the testing equipment. 

rising blood alcohol as a dui defense

What is “Rising Blood Alcohol”

“Rising Blood Alcohol” is a concept in DUI defense that addresses the physiological and temporal aspects of how alcohol is absorbed into the bloodstream. When alcohol is consumed, it doesn’t immediately reach its peak concentration in the blood. Instead, the alcohol must first be absorbed through the gastrointestinal tract before it enters the bloodstream and travels to the liver to be metabolized.

This process means that there is a delay between the time alcohol is consumed and when it reaches its highest concentration in the blood.

If a person is tested for their BAC (Blood Alcohol Concentration) shortly after drinking, their alcohol level may still be rising.

Therefore, their BAC at the time of testing could be higher than it was at the time of driving.

The “Rising Blood Alcohol” defense is used to argue that although the BAC was above the legal limit at the time of testing, it was below the limit while the individual was actually operating the vehicle. This can be an important distinction in DUI cases, where the legality of driving hinges on the specific BAC at the time of vehicle operation.

FAQ: Understanding DUI and Rising BAC Defense

1.)What is rising BAC and how can it affect my DUI case?

Rising Blood Alcohol Concentration (BAC) refers to the physiological increase in alcohol levels in a person’s blood from the time they consume alcohol to the point it reaches its peak. This concept is crucial in DUI defense, as it argues that a driver’s BAC was still ascending at the time of a breath or blood test, potentially leading to a higher reading than what was present during driving. A knowledgeable DUI defense attorney can leverage this in court to challenge the validity of DUI charges.

2.)How does a DUI lawyer use the rising BAC defense?

A DUI lawyer utilizes the rising BAC defense by demonstrating that the timing of the BAC test coincided with the absorption phase when the alcohol level in the bloodstream was still increasing. This defense may argue that although the test showed a BAC above the legal limit, the actual BAC was lower at the time of driving. This approach requires a detailed analysis of the driver’s alcohol consumption pattern and the timing of the test.

3.)What should I do if I’m charged with DUI but believe my BAC was rising?

If you’re charged with DUI and suspect that your BAC was not at its peak while driving, it’s crucial to contact an experienced DUI attorney immediately. The attorney will assess the sequence of your alcohol consumption and the timing of the BAC test to determine if the rising BAC defense is applicable to your case.

4.)Can a preliminary alcohol screening inaccurately measure my BAC?

Yes, preliminary alcohol screenings, like breathalyzers, can sometimes give inaccurately high BAC readings if performed during the alcohol absorption phase. This is because these tests can capture the BAC at a time when it is still rising, potentially leading to results that do not accurately reflect the BAC at the time of driving.

5.)What is the legal definition of BAC and how is it measured?

Blood Alcohol Content (BAC) is a measurement of the amount of alcohol per 100 milliliters of blood, expressed as a percentage. It is typically measured using breath, blood, or urine tests. Each method has its specifications and potential for variability in accuracy, particularly concerning the timing of alcohol absorption and metabolism in the body.

6.)How much alcohol can lead to a DUI charge?

The amount of alcohol that can lead to a DUI charge varies depending on several factors including a person’s body weight, metabolism, and state laws. Generally, driving with a BAC of 0.08% or higher is illegal in most states. However, even lower amounts can impair driving and result in DUI charges.

7.)Why is the timing of alcohol consumption important in a DUI case?

The timing of alcohol consumption is crucial because it directly affects the BAC during a DUI chemical test. If alcohol was consumed shortly before driving and the test was conducted during the absorption phase, the BAC might still be rising. This timing can be a critical aspect of the defense in a DUI case, potentially impacting the charges and outcomes.

Contact DUI Defense Attorney Arja Shah

Arja Shah | Shah Law Firm Arja Shah of Shah Law Firm is a highly skilled DUI defense attorney based in Scottsdale, Arizona, who can provide robust representation in your case. With an extensive background in handling serious DUI cases and a thorough understanding of Arizona DUI laws, Arja Shah has built a reputation for aggressively defending her clients.

Arja Shah has successfully defended over 3,000 clients facing life-altering charges, emphasizing her dedication and commitment to her clients’ rights and well-being. Her practice offers affordable rates and payment plans, ensuring that quality legal representation is accessible to those in need.

For consultations or more information on how Attorney Shah can assist you, visit Arja Shah Law or contact her office directly at (602) 560-7408

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