If you’ve ever been stopped by police on suspicion of drunk driving, you may have heard the term blood alcohol content, or BAC. Your BAC measures how much alcohol is currently in your bloodstream. Generally, the more alcohol you consume, the higher your BAC will rise. The higher your BAC, the greater your level of intoxication.
BAC is particularly important in DUI cases because prosecutors can use it as evidence that a driver was operating a vehicle under the influence of alcohol. Understanding how BAC is measured and what the results mean can be helpful if you’re facing DUI charges.
How is a driver’s BAC determined?
When police suspect someone of drunk driving, they may ask the driver to submit to a chemical test. There are several ways to test for alcohol, although some are more commonly used than others.
Blood tests measure the alcohol directly in a person’s bloodstream. These tests are generally performed by qualified medical personnel.
Breath tests are more common. They require a driver to blow into a device that estimates their BAC based on the alcohol in their breath. Police may use a handheld device during a traffic stop or an evidentiary breath-testing machine after an arrest.
Urine tests may also be used in certain circumstances, although they’re generally reserved for situations involving suspected drug impairment or when other testing methods aren’t available.
What is the legal BAC limit in California?
California has different BAC limits depending on a driver’s age, license and circumstances. Under state law, the limits include:
- Drivers 21 and older: 0.08%
- Drivers under 21: 0.01%
- Drivers operating commercial vehicles: 0.04%
- Drivers transporting passengers for hire: 0.04%
- Drivers on DUI probation: 0.01%
It’s important to understand that a driver can still face DUI charges even if their BAC is below the applicable legal limit. Police may pursue charges if other evidence suggests the driver was impaired.
A DUI conviction can lead to fines, license suspension and possible jail time. However, a BAC test result doesn’t automatically mean a conviction is inevitable. Questions about how the test was administered, whether the equipment was properly maintained and whether police followed the correct procedures may all be relevant to a defense.
If you’re facing DUI charges, experienced legal guidance can help you understand your options and protect your rights.