What Does BAC Stand For?

Posted by Phillip CrawfordAug 05, 2022

            In defending a DUI case, one of the most important elements is the BAC. BAC stands for “Blood Alcohol Concentration,” and is a measurement of how much alcohol is in a person's blood.  Under Vehicle Code Section 23152(b), it is a crime to drive while having a BAC of .08% or higher. It does not matter under this law whether you were actually driving unsafely or whether you were actually impaired by alcohol. If your BAC is above .08% at the time of driving, you can be convicted of a DUI under this law.

How is BAC determined?

In California, after you are lawfully arrested for driving under the influence of alcohol and/or drugs, you are required to submit to a breath or blood test (aka a “chemical test”). Refusing to submit to a chemical test can result in your driving privileges being suspended for at least one year, even if you are found not guilty of DUI.

Blood tests are relatively straightforward: the police draw your blood and hand it off to a laboratory for analysis. Most crime labs in California use a technique called “gas chromatography” to measure the alcohol in your blood.

Breath tests are different. Obviously, when you blow into a breathalyzer, the machine is not analyzing your blood directly. Rather, the machine analyzes your “breath alcohol concentration” or BrAC. The machine reports your BrAC in terms of grams per 210 liters of breath. (For example, if you blow a .09, the machine reports .09g/210L.)  Under California law, there is a specific formula (also known as a “partition ratio”) for converting BrAC to BAC.

Police and Prosecutors believe that the breath tests and blood tests are infallible. However, these BAC tests are frequently flawed and are often performed incorrectly. A skilled DUI attorney can show the flaws in these tests. 

Relevant BACs under California law

In California, there are four different BACs that can be relevant to a DUI case.

  1. .04% - it is unlawful to drive any commercial vehicle with a .04% or higher BAC.
  2. .08% - It is unlawful to drive any motor vehicle at this BAC
  3. .15% - If your BAC is .15% or higher, the Prosecutor can seek to add an “enhancement”, which could trigger additional punishment.
  4. .20% - At this BAC, you can be punished with a longer DUI class and/or a longer suspension of your driving privileges.

How do I know my BAC?

            If you took a breath test, the police can tell you your BAC at the time of your arrest, but they are not required to do so. If you took a blood test, it takes several weeks for the laboratory to analyze your blood.

            After the police arrest you for DUI, they will write a report and send it to the prosecutor. The police report will contain your BAC. Because you are the suspect of a crime, the police will not release the report directly to you. You can only get the report in one of two ways: (1) after your initial court date, the prosecutor is required to send it to you or your attorney; or (2) if you request a DMV hearing, the DMV will send it to you or your attorney.

Just because the police say you had a high BAC, it does not mean that your case is hopeless. A skilled attorney specializing in DUI cases can review your case and identify whether your test results will hold up in court. We have received “not guilty” verdicts in cases where the BAC was as high as 0.28%. That's more than 3 times the legal limit!

            Don't give up without a fight.  Give us a call today and let us fight for you.