BAC

• Driving under the influence occurs in California if a person operates a motor vehicle with a blood-alcohol content (BAC) of more than 0.08 percent by weight. It is unlawful for the operator of a commercial vehicle to have more than 0.04 percent blood-alcohol content. A BAC result above the prescribed limit on a chemical test administered within three hours of driving a vehicle creates the presumption of DUI.
  
  

Chemical Test

• BAC in California is determined by one of three types of chemical tests: blood, breath or urine. Urine tests are also permissible for people with certain health conditions or when the other tests are unavailable. Refusal to submit to a chemical test results in an automatic suspension of one year for a first offense, two years for a second offense and three years for a third offense, but not necessarily a conviction of DUI.
  
  

Penalties

• Conviction of DUI carries penalties that include incarceration, fine and suspension or revocation of the driver's license. A first offense in punishable by 96 hours to six months in jail, a fine of $390 to $1,000 and suspension for four months if a chemical test was administered. A second offense within ten years is punishable by 90 days to one year in prison, a fine of $390 to $1,000 and suspension for one year if a chemical test was given. A third offense within years means at least 120 days to a year in jail, another fine of $390 to $1,000 and revocation of driving privileges.
  
  

Probation

• While a license is suspended for DUI, the driver is considered to be on probation and can apply for a restricted license to get to and from work. While on probation, it is illegal to drive with any measurable amount of alcohol in the blood, and it is illegal to refuse to submit to a chemical test. In counties where a DUI program has been created and approved by the state, a person convicted of DUI with a BAC of less than 0.20 percent must complete at least 30 hours in the DUI counseling program. Arrest for a BAC of more than 0.20 percent in such a county requires completion of 60 hours of counseling.
  
  

Ignition Interlock Device

• California is one of several states that permit the installation of ignition interlocking devices on the cars of DUI offenders. The device is similar to an alcohol breath test. When the device is installed, a breath test is necessary to start the vehicle. Most California counties do not install ignition interlocking devices, but in those that do, installation of the device shortens the probation period.