What is the legal blood alcohol concentration (BAC) limit for drivers over 21 in California?

In California, the legal blood alcohol concentration (BAC) limit for drivers over the age of 21 is set at 0.08%. This level is established to help prioritize road safety and reduce incidents of driving under the influence. At a BAC of 0.08%, a driver's ability to operate a vehicle effectively begins to impair significantly, which increases the likelihood of accidents.

The legal limit is designed based on extensive research showing that at this concentration, drivers experience diminished faculties related to judgment, coordination, and reaction times. Consequently, law enforcement agencies use this standard to determine whether a driver is legally fit to drive and to impose penalties on those who exceed this limit.