California DUI law explained.
A plain-language reference for drivers facing a California DUI charge. Covers the two statutes that define DUI, BAC limits, penalty ranges, the parallel DMV process, and the most common defenses.
The two California DUI statutes
California prosecutes two related DUI offenses under Vehicle Code §23152:
- §23152(a) prohibits driving "under the influence" of alcohol or drugs, meaning your ability to drive safely was impaired. There is no specific BAC threshold for this charge. A prosecutor can win a §23152(a) conviction with field sobriety test failures, driving pattern observations, and officer testimony, even if your BAC was below 0.08%.
- §23152(b) is the "per se" DUI: driving with a blood-alcohol concentration of 0.08% or more, measured within three hours of driving. This is a strict-liability statute. If the prosecution proves you were driving and your BAC was at or above 0.08%, you can be convicted whether or not you were actually impaired.
Most DUI arrests result in both charges being filed in the alternative. Even if one charge is dismissed or reduced, the other can still result in conviction.
Lower BAC limits apply to certain drivers. Commercial drivers face a 0.04% per-se limit (§23152(d)). Drivers under 21 face a 0.01% zero-tolerance limit (§23136). Rideshare and taxi drivers carrying passengers face a 0.04% limit (§23152(e)). Drivers on DUI probation face a 0.01% limit (§23154).
The penalties
California DUI penalties increase sharply with priors. Most relevant priors are DUIs within the previous ten years, though felony DUI priors and wet reckless convictions can also count.
First offense (misdemeanor)
- 3 to 5 years summary (informal) probation
- Fines and assessments totaling $1,800 to $3,600
- 3-month or 9-month DUI program (longer if BAC was 0.20% or higher, or if you refused chemical testing)
- 6-month license suspension by the court, plus a parallel 4-month or 12-month DMV suspension
- Up to 6 months county jail (rare on a clean first offense without aggravators)
Second offense (misdemeanor)
- 3 to 5 years summary probation
- Fines and assessments similar to first offense, plus higher mandatory program cost
- 18-month or 30-month DUI program
- 2-year court-ordered license suspension, with possible restricted license after 90 days if an ignition interlock device is installed
- Mandatory minimum 96 hours county jail, up to 1 year
Third offense (misdemeanor)
- 3 to 5 years summary probation
- 30-month DUI program
- 3-year revocation of driving privilege
- Mandatory minimum 120 days county jail, up to 1 year
- Designation as "habitual traffic offender" for 3 years
Fourth offense or felony DUI
A fourth DUI within ten years, or any DUI causing injury or death, can be charged as a felony under §23153 (DUI causing injury), §23550 (fourth offense), or §23550.5 (DUI with felony prior). Felony DUI carries 16 months to 3 years state prison for a basic fourth-offense felony, and up to 10 years or more for DUI causing serious injury or death. A felony DUI conviction also strips firearm rights, professional licenses, and immigration status.
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The parallel DMV process
A California DUI arrest triggers two separate proceedings that run on independent timelines:
- Criminal court, which decides guilt under §23152 and imposes the criminal penalties listed above. This process can take months to a year or more.
- DMV Administrative Per Se (APS) hearing, governed by Vehicle Code §13558, which separately decides whether your driving privilege will be suspended based on the BAC reading or test refusal.
The two proceedings have different burdens of proof, different rules of evidence, and different decisionmakers. You can be acquitted in criminal court and still lose your license at the DMV, and vice versa. Both must be defended independently.
The 10-day deadline
You have only ten calendar days from the date of arrest to request the DMV hearing. Miss that window and your license is automatically suspended 30 days after the arrest, with no opportunity for review. The 10-day clock starts on the arrest date, not the day you receive notice, not the arraignment, and not the day you hire counsel. Weekends and holidays count. See our DMV 10-day hearing page for details on how to request the hearing and what happens at it.
Common defenses
The viability of any defense depends entirely on the specific facts of the arrest. The most common categories California courts recognize:
Challenges to the stop
Under Terry v. Ohio and the Fourth Amendment, an officer needs reasonable suspicion of a traffic violation or other crime to initiate the stop. If the stop was unlawful, every observation and test that followed may be suppressed. Common bases: pretextual weaving claims that don't survive video review, sobriety checkpoints that fail to meet the constitutional requirements set in People v. Banks, and stops based on anonymous tips that don't meet reliability standards.
Challenges to the chemical test
Breath, blood, and urine tests are challenged regularly. Breath machines (Intoxilyzer 9000, Datamaster, DataMaster DMT in CA) must be calibrated and maintained according to Title 17 of the California Code of Regulations. Blood draws must follow chain-of-custody and storage protocols. Tests delayed too long after driving may not reflect BAC at the time of operation due to rising BAC. Mouth alcohol, GERD, dietary ketosis, and certain medical conditions can produce false high readings.
Challenges to the field sobriety tests
The three standardized field sobriety tests (Horizontal Gaze Nystagmus, Walk-and-Turn, One-Leg Stand) have known accuracy limitations even when administered perfectly. They become unreliable when administered on uneven surfaces, in inadequate lighting, on tired or injured subjects, or by officers who deviate from NHTSA protocols. Most arrests involve at least one deviation that can be exposed in cross-examination.
Constitutional violations
Failure to read Trombetta admonishment for chemical test refusal, Miranda violations during post-arrest custodial interrogation, lack of a contemporaneous interpreter for non-English speakers, and denial of the right to speak with counsel before a blood draw can all suppress evidence.
Rising BAC
Alcohol takes time to absorb. If you had a drink shortly before being stopped, your BAC at the time of driving may have been below 0.08% even if the test 30-60 minutes later showed a higher number. Expert testimony from a forensic toxicologist can establish this.
What happens after a DUI arrest
The first 72 hours after a DUI arrest are the highest-leverage window. Within that time:
- You will receive a pink temporary license that allows you to drive for 30 days while the DMV process plays out
- You should request your DMV hearing in writing within 10 days (deadline is firm)
- You should preserve any potentially exculpatory evidence: dash cam footage from your own vehicle, restaurant or bar receipts that establish what and when you drank, witnesses to your conduct before driving
- You should not discuss the facts of the case with anyone other than your attorney, including in text messages or social media
- You will receive a date for arraignment, typically 30 to 60 days from the arrest, where you will formally enter a plea
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