When a person is on probation for a DUI in California they are prohibited from driving with any measurable amount of alcohol in their system.  In addition, they must submit to a preliminary alcohol screening test.  Should that test show any alcohol .01% bac or above, the driver faces the suspension of their driving privilege for 6 months to 1 year and they can have their court probation violated.
Marin and Sonoma County drivers face an estimated $10,000.00 expense for a first DUI and a conviction for DUI with injury, where someone other than the driver was injured, results in a one year driver license suspension.  Court fines and costs can be more than $2,000.00 and drivers must also pay for attendance at a driving under the influence program and increased insurance premiums.
If you are arrested for drunk driving, or if you get a traffic ticket in Petaluma, San Rafael, Santa Rosa, Novato or anywhere in the Bay Area call an experienced aggressive DUI defense attorney for help.