California DUI Laws Explained
DUI (driving under the influence) questions appear on every California DMV knowledge test, and the rules are stricter than most other states. This guide covers the BAC limits, penalties, implied consent rule, and the specific scenarios you’ll see on the written test.
Blood Alcohol Concentration (BAC) Limits
| Driver | BAC Limit | Legal Reference |
|---|---|---|
| Adult (21+) | 0.08 % | VC §23152(b) |
| Under 21 (Zero Tolerance) | 0.01 % | VC §23136 |
| On DUI probation (any age) | 0.01 % | VC §23154 |
| Commercial driver (CDL) | 0.04 % | VC §23152(d) |
| Passenger-for-hire (rideshare with passenger) | 0.04 % | VC §23152(e) |
Implied Consent
By holding a California driver license, you give implied consent to a chemical test (breath or blood) if you’re lawfully arrested for DUI. Refusing the test:
- First refusal: automatic 1-year license suspension
- Second refusal within 10 years: 2-year suspension
- Third refusal: 3-year revocation
Pre-Arrest Breath Test (PAS)
The roadside Preliminary Alcohol Screening (PAS) is different from the post-arrest chemical test. PAS is voluntary for adults 21+ and mandatory for drivers under 21 (Zero Tolerance) and DUI probationers.
First-Offense DUI Penalties
- License suspension: 6 months
- Fines: $390 – $1,000 base, total often $2,000–$3,000 with court fees
- DUI school: 3, 6, or 9 months
- Probation: 3–5 years informal probation
- Possible jail time: up to 6 months
- Ignition Interlock Device (IID): 6 months on first offense
- Insurance impact: SR-22 filing, premiums often double or triple for 3 years
Second and Third Offense (Within 10 Years)
| Offense | Suspension | Jail (min) | IID | DUI School |
|---|---|---|---|---|
| Second | 2 years | 96 hours | 1 year | 18 months |
| Third | 3 years | 120 days | 2 years | 30 months |
| Fourth (felony) | 4 years | 180 days | 3 years | 30 months + felony record |
Aggravating Factors
- BAC of 0.15 % or higher
- Refusing the chemical test
- Speeding 20+ mph over while intoxicated
- Causing a collision with damage or injury
- Child under 14 in the vehicle
- Hit-and-run combined with DUI
DUI With Drugs (DUID)
California’s DUI laws cover any impairing substance — alcohol, prescription drugs, illegal drugs, or marijuana. There’s no specific BAC equivalent for marijuana; impairment is determined by officer observation, blood test, and Drug Recognition Expert evaluation. Penalties match alcohol DUI penalties.
Open Container Law
Illegal to have an open container of alcohol in any part of the vehicle accessible to the driver, even if no one is drinking and the vehicle is parked. The trunk is the only legal storage. Violations are infractions ($250+ fine).