California DMV Permit Test · Class C Knowledge Test
California DMV Permit Test: Alcohol, Phones, and Licensing Laws Concepts
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Overview
This chapter covers the laws that the test treats as serious: alcohol and drugs, cell phones, seat belts, and what to do after a collision. These rules carry fines, license suspension, and sometimes jail, so the test asks about the exact limits.
For drivers 21 and older, it is illegal to drive with a blood alcohol concentration (BAC) of 0.08% or higher. For drivers under 21, the limit is 0.01%, which is almost zero. By driving in California, you have agreed in advance to take a breath or blood test if an officer lawfully asks; this is called implied consent.
You may not hold a phone in your hand while driving. Adults may use a phone only in hands-free mode, but drivers under 18 may not use a phone at all, even hands-free. Everyone in the car must wear a seat belt.
If you are in a collision where anyone is hurt or killed, or property damage is over $1,000, you must report it to the DMV within 10 days. This report is required even if the police were called and even if the crash was not your fault.
Key concepts
BAC limits
It is illegal to drive with a blood alcohol concentration of 0.08% or more if you are 21 or older, or 0.01% or more if you are under 21.
Memory tipAdults: 0.08. Under 21: 0.01, which is basically zero.
Source: California Vehicle Code (VC 23152, VC 23136) / CA DMV Driver Handbook · as of 2026
Implied consent
By driving in California, you have already agreed to a chemical test (breath or blood) if you are lawfully arrested for driving under the influence. Refusing can lead to losing your license.
Memory tip'Implied' means you said yes when you got behind the wheel.
Source: California Vehicle Code (VC 23612) / CA DMV Driver Handbook · as of 2026
Handheld phone ban
Drivers may not hold a phone or other wireless device while driving. A phone may be used hands-free, or mounted and touched with a single tap or swipe.
Memory tipPhone in hand = ticket. Mount it or leave it.
Source: California Vehicle Code (VC 23123.5) / CA DMV Driver Handbook · as of 2026
Drivers under 18 and phones
A driver under 18 may not use a cell phone at all while driving, not even in hands-free mode, except to call for help in an emergency.
Memory tipUnder 18 = no phone, period.
Source: California Vehicle Code (VC 23124) / CA DMV Driver Handbook · as of 2026
Collision report to the DMV
Report a collision to the DMV within 10 days if anyone was injured or killed, or if property damage was more than $1,000.
Memory tip10 days, $1,000, or any injury. Think 'ten and a thousand.'
Source: California Vehicle Code (VC 16000) / CA DMV Driver Handbook · as of 2026
Seat belts
The driver and every passenger must wear a seat belt. Children must ride in the proper child safety seat or booster for their age and size.
Memory tipEveryone, every seat, every trip.
Often tested
- Watch for 0.08% (21 and older) vs. 0.01% (under 21). Test choices often swap them.
- Hands-free is allowed for adults but not for drivers under 18.
- The DMV collision report is due within 10 days, even if police made a report.
- Implied consent means you already agreed to testing; refusing has its own penalty.
Easy to confuse: Adult driver vs. driver under 18 or 21
| Rule | Adult driver | Younger driver |
|---|---|---|
| BAC limit | 0.08% (age 21 and older) | 0.01% (under 21) |
| Phone use | Hands-free only | No phone at all, even hands-free (under 18) |
3 sample questions
Verified practice questions from this unit.
Question 1. For a driver 21 or older, it is illegal to drive with a blood alcohol concentration (BAC) of:
- ① 0.10% or higher
- ② 0.15% or higher
- ③ 0.08% or higher
▼ Show answer and explanation▲ Hide answer and explanation
Answer: ③ 0.08% or higher
Key point: Age 21+: illegal to drive with BAC 0.08% or more
For drivers 21 and older, driving with a BAC of 0.08% or higher is illegal. You can also be arrested at a lower BAC if alcohol affects your driving.
Wrong answers
- 0.10% or higher: 0.10% is above the legal limit; you would already be over 0.08%.
- 0.15% or higher: 0.15% is far above the legal limit.
Question 2. For a driver under 21, it is illegal to drive with a BAC of:
- ① 0.01% or higher
- ② 0.05% or higher
- ③ 0.08% or higher
▼ Show answer and explanation▲ Hide answer and explanation
Answer: ① 0.01% or higher
Key point: Under 21: illegal to drive with BAC 0.01% or more
California has a zero tolerance rule for drivers under 21. Driving with a BAC of 0.01% or higher is illegal.
Wrong answers
- 0.08% or higher: 0.08% is the limit for drivers 21 and older.
- 0.05% or higher: 0.05% is not a California limit; for under-21 drivers it is 0.01%.
Question 3. Under California law, may an adult driver hold a cell phone in their hand to talk while driving?
- ① Yes, when stopped at a red light
- ② Yes, if the call is short
- ③ No, only hands-free use is allowed for adult drivers
▼ Show answer and explanation▲ Hide answer and explanation
Answer: ③ No, only hands-free use is allowed for adult drivers
Key point: Adults: no hand-held phone use while driving
Drivers 18 and older may not hold a phone while driving. They may use it only in hands-free mode, such as a mounted phone or voice commands. This applies even when stopped at a red light, because you are still driving.
Wrong answers
- Yes, if the call is short: There is no exception for short calls.
- Yes, when stopped at a red light: Stopped at a red light, you are still driving, so holding the phone is still illegal.