What Does BAC Stand For?

What Is Blood Alcohol Concentration (BAC)?

BAC is an abbreviation for Blood Alcohol Concentration (or, sometimes, Blood Alcohol Content). The number indicates the percentage of alcohol in an individual’s bloodstream, providing an objective data point on how much alcohol someone has in their body. For example, a BAC of 0.10% means 1/1000^th of someone’s bloodstream is alcohol.

What Does BAC Measure?

“Contrary to popular belief, BAC does not directly measure how intoxicated someone is,” explains attorney Peter Liss, “it only shows the percentage of alcohol in their bloodstream.” Since all people react to alcohol intoxication differently, the number simply provides an objective way to measure alcohol levels.

A specific number ensures DUI cases do not have to rely solely on officer observation. However, it is still possible to be charged with DUI with a BAC below the legal limit if the officer believes you are intoxicated.

What Is the Legal BAC Limit in California?

For most drivers, the maximum legal BAC level is 0.08%, but some individuals are subject to even lower limits.

California sets different BAC limits depending on the type of driver:

Can You Be Charged With DUI if Your BAC is Below 0.08?

Yes. “While the law states a maximum BAC someone can have before being charged with DUI,” says Liss, “they can still be charged if their test results are lower than this.” Officers can, and do, arrest people with BACs at 0.07% or lower if they believe the individual is driving under the influence.

In these cases, DUI defense lawyers often work to get the charges reduced to wet reckless since there is less objective evidence to prove the allegations.

Visit our page on wet reckless charges to learn more.

What Does a 0.08 BAC Actually Mean?

Some people can down a six-pack of beer and seem relatively normal, while others can barely walk after one cocktail. While everyone reacts differently to alcohol, scientists from the National Highway Traffic Administration have determined that practically everyone drives less safely once their Blood Alcohol Concentration is above 0.08%.¹ At this level of impairment, the vast majority of drivers will demonstrate:

• Slower reaction times
• Poorer judgement
• Reduced coordination
• Distorted perceptions
• Decreased multitasking abilities
• Lowered ability to track objects
• And more

As a result, anyone caught driving with a BAC over 0.08 is considered drunk and can be charged with driving under the influence.

How Many Drinks Is 0.08% BAC?

Image Courtesy of the California DMV Driver’s Handbook

For many people, only two or three drinks are enough to push their blood alcohol concentration to over 0.08%, as seen in this BAC chart from the California DMV handbook. However, these are only general estimates. In fact, your overall BAC is affected by multiple factors, including:²

• Your gender
• Your weight
• Your body fat percentage
• Your overall health
• Your alcohol tolerance
• Your stress level
• Whether you’re tired
• Whether you’re taking any prescription medications
• How quickly you drink your drink
• How long you wait between drinks
• The ABV of the drink
• The actual drink itself
• What else is in your stomach
• And more

Why BAC Matters in DUI Charges

California’s “per se” DUI law means you can be convicted solely for testing above the legal BAC limit, regardless of outward signs of intoxication. If your test result shows your BAC is over 0.08%, the results will be used against you in your DMV hearing and criminal case.

You could also face sentencing enhancements if your BAC is over 0.15%, and even more consequences if it is over or 0.20%. These enhancements could result in more jail time, higher fines, or longer DUI classes.

Similarly, minors face stricter sentencing if their BAC is over 0.05%, and further consequences if it is above 0.08%.

How do Police Measure BAC in DUI Cases?

In California, drivers suspected of DUI are required to submit to a blood or breath test to measure their BAC. “While urine tests can be administered in limited circumstances, they are far less accurate than other BAC tests and are used only in rare cases where neither blood nor breath tests can be provided safely,” explains Liss. Field sobriety tests are considered highly subjective, do not measure BAC, and are not required by law.

How your BAC is measured matters more than you may think in your case, as it can directly affect your defense.

Breathalyzer

A breathalyzer does not directly estimate how much alcohol is in a person’s blood, but instead measures the amount of alcohol in their breath. This distinction is a common basis for many common DUI defenses, as many factors can make the results of a breath test falsely high, including:

• Fevers
• Diet mixers
• Smoking
• Burping just before the breath test
• Low-carb diets
• Diabetes
• Gum disease

Blood Tests

These DUI tests are considered more reliable and allow retests later if you suspect the test was inaccurate. Blood tests can still be challenged if they were incorrectly administered, the sample was improperly stored, or the chain of custody was not properly documented.

Visit our dedicated DUI test page to learn more.

Can You Challenge BAC Results?

“Neither the blood nor the breath test calculates the BAC at the time of driving, which is what matters under the law,” explains Liss. Arguing a driver was under the maximum BAC while driving, even though their alcohol level rose by the time they took a DUI test, is known as the “rising alcohol defense.”

Lawyers can also challenge the result of the blood test or breathalyzer if:

• The officer lacked reasonable suspicion to perform a stop.
• There was no probable cause to perform a DUI test.
• Either test was administered improperly.
• The testing device was not properly calibrated.
• The blood sample was not properly stored, or the chain of command was not properly documented.

For more effective strategies, visit our DUI defense page.

BAC and Drug DUIs

Since there is no test to accurately measure how intoxicated a person is after using drugs, your BAC does not matter in these cases. It also does not matter if the drug was legal or even prescribed to you by a doctor. You can be charged with a drug DUI any time the officer believes you were under the influence of another substance.

“Drug DUI charges can be particularly complex and require experienced lawyers because the case essentially comes down to whether or not you used a substance that could affect your ability to drive and if your driving was, in fact, affected by the substance,” says Liss.

Learn more about drug DUIs here.

How a DUI Defense Lawyer Can Help

A defense attorney can play a critical role in helping you challenge your BAC results after a California DUI, showing you weren’t over the legal limit. Depending on the circumstances of your case, an attorney can:

• Represent you at the DMV hearing.
• Challenge the legality of the traffic stop and arrest.
• Fight the DUI test results.
• Work to have the charges dropped.
• Attempt to have the enhancements dropped.
• Negotiate a winning plea bargain.
• Represent you at the trial.
• Fight to minimize your sentence or secure alternative sentencing when possible.

Attorney Peter Liss has over 40 years of experience fighting these charges and can help you challenge your BAC results.

If you have been charged with a DUI, please call (760) 643-4050 to schedule a free initial consultation.