Underage drivers (motorists who are under the age of 21) who operate a vehicle while "under the influence" or with a blood alcohol concentration (BAC) of .08% or higher can be charged with a "standard" DUI and generally face the same penalties as drivers who are at least 21 years old.
However, underage drivers in California can also be convicted of a "zero-tolerance" offense for having a BAC of .01% or an "underage DUI" for having a BAC of .05% or more. In other words, California has two types of DUI restrictions that apply to underage drivers.
California's "implied consent" laws require minors who are lawfully detained for DUI to submit to a preliminary alcohol screening test (breathalyzer). Underage motorists who are caught driving with a BAC of .01% or more can be convicted of a zero-tolerance offense, which is an infraction.
A zero-tolerance conviction carries up to $250 in fines and a minimum one-year license suspension.
An underage driver with a BAC of .05% or more can be charged with underage DUI, an infraction.
Strangely, the penalties for an underage DUI typically aren't more severe than those for a zero-tolerance offense. Drivers convicted of an underage DUI face a one-year license suspension and a $100 to $300 fine (depending on whether the driver has prior infraction convictions within the past 12 months). Drivers who are under 21 but at least 18 years old must also complete an alcohol education program as a condition of license reinstatement.
A zero-tolerance offense won't add points to the motorist's driving record. However, an underage or standard DUI conviction will result in two demerit points being assessed to the person's record. Accumulating too many points can lead to license suspension.
Regardless of the charge, it's always best to talk to an experienced DUI attorney if you've been cited for driving under the influence. A qualified lawyer can tell you how the law applies to your situation and help you decide on the best course of action.