Alcohol and drugs

California's DUI law covers alcohol and every drug that affects your driving. It makes no difference whether a drug is illegal or comes from a doctor or a pharmacy: cough syrup, prescriptions and over-the-counter medicines all count. Read labels and know what you take. Your tolerance to alcohol also goes down as you get older.

BAC limits. Blood alcohol concentration (BAC) measures the alcohol in your blood. It is illegal to drive with a BAC of:

• 0.08% or more if you are over 21.

• 0.01% or more if you are under 21.

• 0.01% or more, at any age, while on DUI probation.

• 0.04% or more in a vehicle that needs a commercial license, or while driving a passenger for hire.

Being under the limit is not permission. Even one drink affects you, and if you are impaired you can be arrested and convicted of DUI without any BAC measurement.

In the vehicle. No one, driver or passenger, may drink alcohol or smoke or eat cannabis in a vehicle. Alcohol or cannabis you carry must be sealed and unopened; an opened container goes in the trunk or somewhere passengers do not sit, and never in the glove box. These rules do not apply to passengers in a bus, taxi, camper or motorhome.

Testing and arrest. Driving in California counts as agreeing to a breath, blood or urine test whenever an officer suspects DUI. After a breath test you may still have to give blood or urine to check for drugs. Refusing means DMV suspends or revokes your privilege for one year. After a DUI arrest, DMV must suspend your privilege (the Administrative Per Se law); the officer may take your license and give you a temporary one for 30 days, and you have 10 days from the arrest to request a DMV hearing.

Conviction. DMV suspends or revokes your privilege. You must complete a DUI program, file an SR 22/SR 1P and pay reissue or restriction fees, and you may need an ignition interlock device. You may also face up to six months in jail, a fine, impound and storage fees, and lawsuits if you hurt or kill someone. A DUI stays on your record for 10 years, and another one in that time brings more penalties.

Under 21. You may carry alcohol only with someone 21 or older present, and only full, sealed and unopened (opened: in the trunk). The exception is working for someone with an off-site liquor license. Caught with alcohol: impound up to 30 days, a fine, and a one-year suspension or a delay of up to a year for your first license. An officer may require a hand-held breath test, a PAS or another chemical test. A PAS of 0.05% or more can lead to a breath or blood test, and a later result of 0.05% or more to a DUI arrest. A DUI at 0.01% or more can mean a one-year revocation and a DUI program. Aged 13 to 20, a conviction for riding a bicycle under the influence can suspend or delay your driving privilege for a year.

Alcohol and drugs are also illegal when you operate a boat, jet ski or similar vessel.