Study by test section.
Free CDL study guides for General Knowledge, HazMat, Air Brakes, Combination Vehicles, Doubles & Triples, Pre-Trip Inspection, and Tanker. Start with the section you need and work through the material at your own pace.
Best order to study
Build your study path.
- Start with General Knowledge.
- Add Air Brakes if your vehicle uses an air brake system.
- Move into Combination Vehicles for most Class A paths.
- Study HazMat, Tanker, or Doubles & Triples only if your route or job requires them.
- Finish with Pre-Trip review before exam day and road test prep.
Not every driver needs every endorsement. Study the sections that match your license path and job goal.
What you'll get
Inside each guide.
- Key rules explained in plain English
- High-priority test topics by section
- Common mistakes to avoid
- Direct paths into practice questions
Choose your guide
Which guide do I need?
Each guide breaks down the rules, test topics, and must-know points for that CDL section. Start with General Knowledge if you are not sure where to begin.
Core permit path
Begin with the sections required for your CDL class and vehicle.
General Knowledge
The core written test for most CDL applicants. The best starting point if you are new to CDL study.
Open guide →Air Brakes
Essential if your vehicle uses air brakes. Covers PSI ranges, warning devices, and the brake check sequence.
Open guide →Combination Vehicles
Required for tractor-trailer paths. Focuses on coupling, uncoupling, trailer swing, and rollover prevention.
Open guide →Endorsements & skills test
Add only the sections that match your cargo, trailer, or test plan.
Hazardous Materials
For transporting hazardous cargo. Covers placards, shipping papers, and safety rules you must know.
Open guide →Tanker (N)
For hauling liquid cargo in bulk tanks. Emphasizes surge control, stopping distance, and safe tank handling.
Open guide →Doubles & Triples
For pulling more than one trailer. Covers converter dollies, crack-the-whip effect, and multi-trailer handling.
Open guide →Pre-Trip Inspection
Helps you pass the inspection portion and understand what examiners expect during the walk-around.
Open guide →FAQ
Common study questions.
Which CDL study guide should I start with?
Start with General Knowledge unless you already know your employer or training path requires a specific endorsement first.
Do I need all CDL endorsements?
No. Most drivers only need the sections that match their license class, vehicle type, and cargo type.
Is General Knowledge enough for the permit test?
It is the core written section for most applicants, but many Class A and specialty paths also require Air Brakes, Combination Vehicles, or other endorsements.
What is the difference between a study guide and a practice test?
The study guide teaches the rules and concepts. The practice test helps you apply them under exam-style conditions.
Are these CDL study guides free?
Yes. You can read the guides free and use them to decide where to practice next.
How do I know if I need HazMat, Tanker, or Doubles & Triples?
That depends on the type of vehicle and cargo you plan to operate. If your route involves hazardous materials, tank vehicles, or multiple trailers, study that section.
Next step
Choose the test you want to diagnose.
Reading teaches the rule. A module-specific practice test shows whether you can apply it without the guide and which section to study next.
Start a practice test
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