In California a driver under 21 may not drive with a blood alcohol concentration (BAC) of 0.01% or higher. If a test shows 0.01% or more, the DMV suspends the driving privilege for one year. For drivers 21 and older the limit is 0.08%. At any age, it is illegal to drive impaired by any drug, including prescription medicine and cannabis.
What is the BAC limit for drivers under 21?
The limit for drivers under 21 is 0.01% BAC, which is often called zero tolerance. Vehicle Code 23136 makes it unlawful for anyone under 21 with a BAC "of 0.01 percent or greater" to drive. The test can be a preliminary alcohol screening (PAS) test, a hand-held breath test, or another chemical test.
A second rule applies at 0.05%. Vehicle Code 23140 makes it unlawful for a person under 21 to drive with 0.05% or more. The handbook explains what happens next: if the PAS shows 0.05% or higher, the officer may require a breath or blood test. If that test also shows 0.05% or higher, the driver may be arrested for DUI.
| Driver | Illegal to drive at |
|---|---|
| Under 21 | 0.01% or higher |
| Under 21 (separate offense, VC 23140) | 0.05% or higher |
| 21 and older | 0.08% or higher |
| Any age, on DUI probation | 0.01% or higher |
| Driving a vehicle that needs a commercial license | 0.04% or higher |
| Driving a passenger for hire | 0.04% or higher |
A legal BAC does not mean a safe driver. The handbook warns that almost everyone feels the effects of alcohol below the legal limit. A driver can be arrested and convicted of DUI even without a BAC measurement.
What happens to a driver under 21 who tests at 0.01% or more?
The DMV suspends the driving privilege for one year. The DMV's DUI page covers a driver under 21 whose PAS or other chemical test shows 0.01% or more. In that case the privilege "will be suspended for one year" by the DMV. This is an action on the license, separate from anything a court does.
- Court conviction, ages 15 to 20. After a conviction for using alcohol or a controlled substance, the court orders the DMV to suspend the privilege for one year. If the teen has no license yet, eligibility is delayed instead.
- Alcohol in the car. An under-21 driver caught with alcohol in the vehicle can have the vehicle impounded for up to 30 days. The court may fine the driver and suspend the license for one year, or delay a first license for up to one year.
- Bicycle DUI, ages 13 to 20. A conviction for riding a bicycle under the influence can also cost the license. The privilege may be suspended or delayed for one year.
- Turning 18 does not end it. The handbook says turning 18 "does not erase or end" a suspension, restriction or probation.
What is implied consent, and what if you refuse the test?
Implied consent means that by driving in California, you have already agreed to be tested. In the handbook's words, "you consent to a breath, blood, or urine test" when an officer suspects DUI. For drivers under 21, Vehicle Code 23136 adds consent to a PAS test when lawfully detained.
Refusing does not avoid a penalty. The DMV sets these results for a driver under 21 who refuses or does not finish a PAS or other chemical test.
| Refusal | Result |
|---|---|
| First offense | One-year suspension |
| Second offense within 10 years | Two-year revocation |
| Third or later offense within 10 years | Three-year revocation |
After a DUI arrest, the officer may take the license and issue a temporary license for 30 days. The handbook says you may request a DMV administrative hearing within 10 days of the arrest.
Where can alcohol or cannabis ride in a car?
Any alcohol or cannabis in the car must be sealed and unopened, or kept in the trunk. If there is no trunk, an open container must go where passengers do not sit. The glove box does not count as a safe place, and the handbook names it as illegal for an open container.
- No one in the car, driver or passenger, may drink alcohol or smoke or eat cannabis products while driving or riding.
- A driver under 21 may not carry alcohol unless a person 21 or older is with them. Even then, the container must be "full, sealed, and unopened" or kept in the trunk.
- The rule does not apply to passengers in a bus, taxi, camper or motorhome.
Do the same rules apply to cannabis and prescription drugs?
Yes. California's DUI laws cover drugs the same way they cover alcohol. The handbook says the law sees no difference between illegal drugs and "medications you get from a doctor or pharmacy" when they affect driving. Cannabis, prescriptions, over-the-counter medicine and even cough syrup can all lead to a DUI if they affect your driving.
- Read medicine labels and know how a drug affects you before you drive.
- Mixing alcohol and drugs is illegal when the mix lowers your ability to drive safely.
- Passing a breath test does not end the stop. The officer may still require a blood or urine test to look for drugs.
What does the permit test ask about alcohol and drugs?
Expect questions on the facts in handbook Section 9: the BAC limits, implied consent and open containers. One of the DMV's own sample tests asks when it is legal to drive with an opened alcohol container. The answer is when it is in the trunk, not under the seat or in the glove box.
Study the BAC table above until you can say each number from memory. The four to know are 0.01% under 21, 0.05% for the separate under-21 offense, 0.08% for adults and 0.04% for commercial and for-hire drivers. Our permit test study plan shows how to fit Section 9 into your review.
Quick answers
Check yourself
Sources
- California Driver's Handbook, Section 9: Alcohol and Drugs (opens in a new tab)
- California DMV: Driving Under the Influence (DUI) (opens in a new tab)
- California Vehicle Code 23136 (under 21, 0.01% BAC) (opens in a new tab)
- California Vehicle Code 23140 (under 21, 0.05% BAC) (opens in a new tab)
- California Driver's Handbook, Section 7: Laws and Rules of the Road (Continued), minor's license (opens in a new tab)
- California DMV: Sample Class C Written Test 4 (opens in a new tab)
Checked: October 5, 2026. Rules and forms can change; recheck the official page before acting.
See something wrong or out of date? Report a mistake on this page. We read every report and fix confirmed mistakes.