Free CDL Test Prep

Pass Your CDL Knowledge Test

Practice General Knowledge, Air Brakes, HazMat, Combination Vehicles, and all endorsements with real-style questions and instant pass/fail scoring.

67
Practice Questions
6
Knowledge Tests
80%
Required to Pass
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Choose Your Test

General Knowledge

Required

Required for ALL CDL applicants. 50 questions, 80% to pass.

Air Brakes

Essential

Required to drive vehicles equipped with air brakes.

Combination Vehicles

Class A

Required for Class A CDL (semi-trucks, tractor-trailers).

Hazardous Materials

Endorsement H

Required for HazMat endorsement (H). Background check required.

Passenger Transport

Endorsement P

Required for Passenger endorsement (P). Buses and vans.

Tank Vehicles

Endorsement N

Required for Tank endorsement (N). Liquid/gas tankers.

CDL Classes

Class A
Tractor-Trailer

Any combination vehicle with GCWR 26,001+ lbs, towed unit over 10,000 lbs. Includes semi-trucks, flatbeds, tankers.

Class B
Straight Truck / Bus

Single vehicle 26,001+ lbs. Includes dump trucks, box trucks, city buses, and most RVs.

Class C
Passenger / HazMat

Smaller vehicles carrying 16+ passengers or placarded hazmat that don't qualify as Class A or B.

Why Practice Here?

Pass/Fail Scoring

Every test shows exactly whether you hit the 80% threshold required by FMCSA.

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Real-Style Questions

Questions modeled after the actual CDL knowledge exam with detailed explanations.

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All Endorsements

Practice for H, N, P, T, S, and X endorsements in one place.

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Frequently Asked Questions

How many questions are on the CDL General Knowledge test?

The CDL General Knowledge test has 50 questions. You must answer at least 40 correctly (80%) to pass. It covers topics like vehicle inspection, basic controls, shifting, backing, coupling/uncoupling, pre-trip inspection, and hazardous materials basics.

What is the passing score for CDL knowledge tests?

You must score at least 80% on all CDL written knowledge tests. For the General Knowledge test, that means 40 out of 50 questions correct. For endorsement tests, the number of required correct answers varies by state.

What CDL endorsements are there?

CDL endorsements include: H (Hazardous Materials), N (Tank Vehicles), T (Doubles/Triples), P (Passenger Transport), S (School Bus), and X (combination of H and N). Each requires passing a separate written knowledge test.

What is the difference between CDL Class A, B, and C?

CDL Class A covers combination vehicles with a GCWR of 26,001+ lbs where the towed unit exceeds 10,000 lbs (semi-trucks). Class B covers single vehicles 26,001+ lbs or towing up to 10,000 lbs (dump trucks, buses). Class C covers vehicles carrying 16+ passengers or hazmat that don't qualify as Class A or B.

Do I need Air Brakes endorsement for a CDL?

You don't need a separate Air Brakes endorsement — instead, if you fail the Air Brakes knowledge test or take your skills test in a vehicle without air brakes, your CDL will have an 'Air Brakes Restriction' (L restriction). To drive vehicles with air brakes, you must pass the Air Brakes written test.