Drinking alcohol affects your Blood Alcohol Concentration (BAC).
By DUI laws in California, it is illegal for any person to operate:
- A motor vehicle with a BAC of 0.08% or higher.
- Any vehicle requiring a commercial driver license (with or without a commercial driver license issued to the driver), with a BAC of 0.04% or higher.
- A motor vehicle with a BAC of 0.01% or higher, if the person is under age 21.
- A motor vehicle with a BAC of 0.01% or higher at any age if the person is on DUI probation .
See BAC Calculator  to estimate the concentration of Alcohol in your blood based on how much you have been drinking.