In California, a person arrested for DUI faces two separate proceedings -- one legal, one administrative. The first is the criminal process: arrest by the officer, charge and court proceedings. The second is the administrative process: seizure of the license by the police, service of a notice of driver's license suspension (and 30-day temporary license), and the right to demand a hearing to contest the suspension. A detailed discussion of the California DMV license suspension is located on this website.
The driver's license suspension is not for driving under the influence. Often called an "administrative per se suspension", it is for driving with a blood-alcohol concentration of .08% or higher, or for refusing to submit to a breath or blood alcohol test. Impairment or intoxication are not issues.