Alcohol in the Blood: Understanding BAC Levels in California

By San Diego Attorney on January 10, 2021

A person’s blood alcohol concentration (BAC) is one of the key elements used by district attorneys to convict them of driving under the influence (DUI) in the state of California. Generally, if a police officer suspects someone of driving while intoxicated, the officer can pull them over and request a breathalyzer test to measure the driver’s BAC. If the driver has a BAC level of 0.08% or higher, then the officer can arrest the driver for DUI. However, BAC tests are not foolproof, and there are several factors that can influence the test to show a positive result, even if you have not had any alcohol.

How California Defines DUIs

In the state of California, driving under the influence of any amount of alcohol can result in a DUI charge. This is because our state has two main DUI charges for adults: driving under the influence of alcohol and driving under the influence of alcohol with a BAC of 0.08% or higher. The first scenario refers to California Vehicle Code Section 23152(a) VC, which makes it illegal to drive with any amount of alcohol in your system. Under this statute, prosecutors can charge you with a DUI even if you register a BAC below 0.08%. However, these charges are typically harder to prove in court without significant evidence, and you may be eligible for a wet reckless plea if this is your first offense.

That being said, if you do register a BAC at or above 0.08%, then the prosecution could pursue a charge under California Vehicle Code Section 23152(b) VC, which is the main DUI charge that most people are aware of. However, what most people do not realize is that California has several different BAC limits depending on your age and what type of vehicle you are operating. According to the California DMV, BAC legal limits are as follows:

• For drivers who are 21 or older, the BAC legal limit is 0.08%
• For drivers who are under 21, the BAC legal limit is 0.01%
• For drivers who are on probation for a DUI, the BAC legal limit is 0.01%
• For drivers who operate commercial vehicles with a CDL, the BAC legal limit is 0.04%
• For drivers for rideshare or cab companies, the BAC legal limit is 0.04%

In addition, the higher your BAC at the time of arrest, the more severe your punishments can be. Both criminal courts and the DMV can extend the length of your jail sentence and license suspension based on your BAC. This is why it is important to have a strong defense team on your side who can call into question the validity of your BAC test.

How Is BAC Tested?

Police officers are trained to perform several tests to see if someone is driving while intoxicated, but BAC is measured specifically through a defendant’s breath or blood using certified testing equipment. While you can refuse a test, by default, all drivers in California consent to drug and alcohol testing if a police officer suspects them of driving under the influence. If you do refuse to be tested, then your license will automatically be suspended by the DMV. However, even if you do agree to be tested, it is important to understand how a positive result is obtained and how to disprove it.

The most common device police officers use to test BAC is a breathalyzer, which measures the amount of alcohol in a driver’s breath. As blood passes through your lung, each time you breathe, particles of alcohol are being exhaled. A breathalyzer is designed to detect these particles and estimate how much alcohol is in your blood.

However, there are several issues with this test. For one, breathalyzers do not take into account a person’s weight, height, body chemistry, or metabolism. These differences in body type can influence the results of a test, even showing a false positive.

The other method that officers can use to test BAC is a blood test. Typically, officers will rely on a breathalyzer test because it is easier and more efficient, but they can request blood tests if necessary. This varies depending on the police department, what resources are available, and the nature of the arrest. If someone was injured in an accident, police officers may request a BAC blood test for one or both drivers, and even a urine test, to confirm someone committed a DUI with injury. Blood tests are more accurate than breathalyzers, but lab errors do occur that result in false positives.

In any situation, if you have been charged with a DUI in San Diego or North County, you should not hesitate to contact jD LAW. Our San Diego DUI defense attorney is a former LAPD investigator who has extensive experience on both sides of DUI cases. He can thoroughly review the charges against you, call into question the officer’s actions during the arrest, and raise doubts about the validity of your BAC test results. To get started on your defense, call our office at (760) 630-2000 to schedule a free consultation.