What is a rising BAC defense?

Q:

What is a rising BAC defense?

A:

It is illegal in every state to operate a motorized vehicle with a blood alcohol concentration (BAC) of 0.08% or higher. Drivers who are stopped and arrested for suspicion of DUI are generally required to submit to a chemical test of their blood, breath or urine. Drivers over the age of 21 who have a BAC of 0.08% or higher can be arrested for a per se DUI without any additional evidence of driver impairment.

Due to the absorption rate of alcohol in the body, however, drivers may become more intoxicated, not less, after consuming alcohol. For this reason, chemical tests performed too long after driving may not accurately reflect the driver’s true blood alcohol concentration at the time of driving, leading to a potential defense referred to as the rising BAC defense.

What is blood alcohol concentration?

Blood alcohol concentration or blood alcohol content, as it is also called, is the measure of the percentage of alcohol in a driver’s blood. For instance, drivers with a BAC of 0.10% have 1 milliliter of alcohol for every 1,000 milliliters of blood.

Although it is illegal in every state for a driver to operate a motorized vehicle with a blood alcohol concentration of 0.08% or higher, negative affects to a driver’s thoughts, judgment, concentration, coordination, reaction time and emergency response can be impaired or lessened with a blood alcohol concentration as low as 0.01% to 0.06%.

How is alcohol absorbed in the body?

So, how is alcohol absorbed in the body? When an individual takes their first drink, the alcohol absorption begins immediately. The stomach and small intestines process the alcohol, and it is digested and absorbed into the bloodstream. The alcohol then moves to other parts of the body, including the liver. The liver’s absorption rate of alcohol is much slower than the stomach. In fact, it can take the liver up to an hour to break down one unit of alcohol.

Alcohol absorption rates can also be affected by many other factors. For example, food consumption can substantially slow the absorption rate of alcohol in the stomach. Additional factors such as the size and weight of the drinker, the type of drink consumed, the age of the drinker, and the gender (women are generally smaller and weigh less than men) can also increase or reduce alcohol absorption rates.

Understanding the Rising BAC Defense

Alcohol concentration and the absorption rates are all factors in the notion of the rising BAC defense. Drivers who are arrested for driving under the influence of alcohol may be able to prove that although their blood alcohol concentration was above the legal limit when they were tested for DUI, it was not above the legal limit while they were actually driving. In fact, because it takes alcohol hours to be absorbed into the body, if the police waited too long to perform the chemical test, a driver's BAC may have risen above the legal limit after they drove.

For example, a driver who tested over 0.08% an hour or more after driving may have actually had a BAC of 0.06 or .07% while driving. And driving with a BAC under 0.08% is not necessarily illegal unless the state can prove that the driver was not able to safely operate their motorized vehicle. To prove this, however, the state will need solid evidence that the driver’s actions were reckless, unsafe or dangerous.

When can a driver use the rising BAC defense?

To use the rising BAC defense, drivers will generally need to hire a DUI lawyer. The DUI lawyer may need to hire a toxicology expert who can review the facts of the driver’s case. Specifically, how the driver’s BAC was established, the approximate BAC at the time of driving, and the amount of time that the police waited to test the driver’s BAC after the DUI arrest.

Not all drivers will be able to successfully defend their DUI case with the rising BAC defense. This defense is best used when specific factors are present in the DUI arrest. For example, the rising BAC defense is most effective if the driver’s BAC was close to the legal limit at the time of the DUI arrest, there was an extended delay by the police to test the driver’s blood, and there were no other significant signs that the driver was intoxicated (i.e., the driver was not involved in an accident).

If there were other clear signs that the driver was intoxicated, the state may be able to prove that the driver was unable to safely operate their vehicle without performing a chemical test.

Bottom line: It can take between 45 minutes and three hours for alcohol to be absorbed in a driver’s body. For this reason, a driver’s blood alcohol concentration may continue to rise long after they are stopped and arrested for driving under the influence of alcohol.

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Whether you're facing a legal issue or just seeking information, Justipedia aims to be your most trusted resource for legal information on the Web. With the help of legal professionals across the country, we put the law in plain language to help answer your top legal questions.

Justipedia was founded by Internet veterans Cory Janssen and Mitchell Allen. Janssen founded Investopedia.com and grew it one of the largest investing sites on the Web. Allen is an author, speaker and the founder of LeadRival, the leading provider of pay-per-action advertising in consumer legal services.

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