California DUI Laws in a Nutshell

In California, it is a misdemeanor to drive a vehicle under the following circumstances:

• While under the influence of any alcoholic beverage or drug, or under their combined influence. Veh C §23152(a).

— DUI involving alcohol. It is not necessary to prove any specific degree of intoxication, but only that the defendant was under the influence. A person is under the influence when, as a result of using alcohol or drugs, his or her physical or mental abilities are impaired to such a degree that he or she no longer has the ability to drive the vehicle with the caution characteristic of a sober person of ordinary prudence under the same or similar circumstances.

— DUI involving drugs. When a defendant is charged with driving under the influence of a drug, a showing of a specific measurable amount of the drug in the defendant’s blood is not required. The showing that must be made is that the defendant was under the influence.

• While having 0.08 percent or more, by weight, of alcohol in one’s blood. For this offense it is not necessary to prove the defendant was, in fact, under the influence; it is sufficient to prove the defendant’s blood-alcohol level was 0.08 percent or more.  For this reason, this statute is sometimes referred to as the “per se” DUI statute. There is a rebuttable presumption that the person had 0.08 percent or more, by weight, of alcohol in his or her blood at the time of driving the vehicle if the person had 0.08 percent or more, by weight, of alcohol in his or her blood at the time of the performance of a chemical test within three hours after driving.

Veh C §23152(b). The percent by weight is based on grams of alcohol per 100 milliliters of blood or grams of alcohol per 210 liters of breath. Veh C §23152(b).

• While addicted to the use of any drug, unless participating in a narcotic treatment program approved under Health & S C §§11875 et seq. Veh C §23152(c).

• While having 0.04 percent or more, by weight, of alcohol in one’s blood while driving a commercial vehicle. Veh C §23152(d).

There is a rebuttable presumption that the person accused of DUI had 0.04 percent or more, by weight, of alcohol in his or her blood at the time of driving the vehicle if the person had 0.04 percent or more, by weight, of alcohol in his or her blood at the time of the performance of a chemical test within three hours after driving.  Veh C §23152(d).