California CDL Study Guide
California issues commercial driver licenses through the Department of Motor Vehicles (DMV). The state follows federal CDL rules and adds its own behind-the-wheel training requirement. You can drive a commercial vehicle inside California at 18. You must be 21 to drive across state lines or carry hazardous materials.
Key California numbers
- Minimum age (intrastate): 18
- Minimum age (interstate or hazmat): 21
- CLP hold before skills test: at least 14 days
- General Knowledge passing score: 80%
- General Knowledge test: ~50 questions
- Air Brakes test: ~25 questions (required if your vehicle has air brakes)
- Combination Vehicles test: ~20 questions (required for Class A)
Topics on the California General Knowledge test
- Vehicle inspection (pre-trip, en-route, post-trip)
- Driving safely (speed management, space management, hazard perception)
- Transporting cargo safely
- Air brakes (if your vehicle is air-braked)
- Combination vehicles (Class A)
If you fail a test
If you fail a CDL knowledge test in California, there is no waiting period to retake it. You are allowed 3 attempts to pass the knowledge test(s) on a single application. You are allowed a total of 3 attempts to pass the skills test on a single application. Each failed segment of the skills test (vehicle inspection, basic control skills, or road test) counts as one skills test failure.
Frequently asked questions
How old do I need to be to get a CDL in California?
You must be at least 18 to drive a commercial vehicle inside California. You must be 21 to drive across state lines or carry hazardous materials.
How long must I hold my California CLP before the skills test?
You must hold your Commercial Learneru0027s Permit for at least 14 days before you can take the CDL skills test.
How many questions are on the California CDL general knowledge test?
The general knowledge test has 50 questions. You must answer at least 40 correctly to pass, which is 80%.
Do I need to take Entry-Level Driver Training in California?
Yes. If you are getting your first Class A or B CDL, or your first H, P, or S endorsement, you must complete federal ELDT. California also requires at least 15 hours of behind-the-wheel training.
Do I need a DOT medical card to get a California CDL?
Yes. You must complete a DOT medical exam and submit the MER and Medical Examineru0027s Certificate forms to the DMV.
What if I fail the CDL knowledge test?
There is no waiting period to retake a failed CDL knowledge test in California. You are allowed up to 3 attempts on a single application.
Free practice
Start a California General Knowledge quiz →
Sources: California DMV Commercial Driveru0027s Licenses page California Commercial Driver Handbook (PDF) California Commercial Driver Handbook - Section 1 Introduction California DMV Truck Drivers special interest page