CDL Prep HeroStudy for your CDL permit test with answers explained.
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Start with General KnowledgeWhich tests do you need?
Before you can get your CDL learner's permit, you pass written knowledge tests. Which ones depend on the vehicle you'll drive. Endorsements add a test for special kinds of driving, like hauling hazmat or carrying passengers. Every test takes 80% to pass. See our study guides for test preparation tips, or read which CDL rules are already set for 2027.
| Test | Who takes it | Typical length |
|---|---|---|
| General Knowledge | Everyone getting a CDL | About 50 questions |
| Air Brakes | Anyone driving a vehicle with air brakes | About 25 questions |
| Combination Vehicles | Class A (tractor-trailer) drivers | About 20 questions |
| Endorsements | ||
| HazMatH | Drivers hauling hazardous materials that need placards | Varies by state |
| Tank VehiclesN | Drivers hauling liquids or gases in a tank | About 20 questions |
| Doubles/TriplesT | Class A drivers pulling double or triple trailers | About 20 questions |
| PassengerP | Drivers of buses and other passenger vehicles | About 20 questions |
| School BusS | School bus drivers (along with Passenger) | About 20 questions |
Question counts vary by state. Check your state's CDL manual. See which of the eight free tests you need.
After the permit, the skills test starts with a vehicle inspection. Read the pre-trip inspection guide.
Find CDL practice tests by state for state-specific manuals and resources. Looking for CDL training? Check if your school is FMCSA-registered or browse CDL schools by state.
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