How Many Questions Are on the CDL General Knowledge Test?

Before you walk into the DMV, you should know exactly what you're facing. The CDL General Knowledge test is the foundation of your CDL — every driver must pass it. Here's a complete breakdown of the test format, question counts by section, and what you need to score to pass.

The Basics: 50 Questions, 80% to Pass

The CDL General Knowledge test contains exactly 50 multiple-choice questions. You must answer at least 40 correctly to pass — that's an 80% minimum passing score. Each question has four answer choices (A, B, C, D).

The test is based on the AAMVA CDL Manual, which is the national standard used by all 50 states. Your state may have a slightly different manual, but the content is essentially the same.

Question Distribution by Section

The General Knowledge test draws from multiple sections of the CDL manual. Here's an approximate breakdown of how many questions come from each area:

Section	Approx. Questions	% of Test
Driving Safely	8–10	16–20%
Pre-Trip Inspection	6–8	12–16%
Shifting and Backing	4–6	8–12%
Seeing Hazards	3–5	6–10%
Skid Control	3–4	6–8%
Emergencies	3–4	6–8%
Dangerous Conditions	3–5	6–10%
Transporting Cargo	4–6	8–12%
Hazardous Materials (Basic)	2–3	4–6%
Vehicle Inspection	3–5	6–10%

Note: These are approximate distributions. The actual questions are pulled from a test bank, so each test will vary slightly. The total always equals 50 questions.

How the CDL Test Works (The Process)

Step 1: Visit Your State DMV/MVD

You take the CDL written test at your state's Department of Motor Vehicles (or equivalent agency). Most states now offer the test on a computer terminal, though a few still use paper tests.

Step 2: Show Your ID and Pay the Fee

You'll need a valid driver's license, proof of identity, Social Security number, and proof of state residency. CDL permit fees vary by state but typically run $25–$80.

Step 3: Take the Test

The test is not strictly timed at most DMVs — you'll typically have 60–90 minutes but can take longer if needed. Read each question carefully. Many questions are designed to trip up drivers who skim.

Step 4: Results and CLP

You'll know your score immediately. Pass and you walk out with your Commercial Learner's Permit (CLP). Fail and you'll need to wait before retesting (waiting periods vary by state, typically 1–7 days).

Endorsement Tests You May Need to Take the Same Day

If your job requires operating vehicles with air brakes (almost all commercial trucks), you'll need to pass the Air Brakes test the same day or have an air brake restriction on your CLP. Plan ahead:

• Air Brakes: 25 questions (required for most Class A jobs)
• HazMat: 30 questions (needed for HazMat endorsement)
• Combination Vehicles: 20 questions (required for Class A tractor-trailers)
• Tanker: 20 questions
• Doubles/Triples: 20 questions
• Passenger: 20 questions (for bus drivers)

Key Numbers You Must Memorize

The General Knowledge test includes specific numerical thresholds that appear frequently. Memorize these:

• Passing score: 40/50 (80%)
• Minimum following distance (clear weather): 1 second per 10 feet of vehicle length
• At 40 mph, a truck needs roughly 200 feet to stop
• At 55 mph, stopping distance is approximately 400 feet
• Air pressure warning buzzer activates at 60 PSI
• Normal air brake operating pressure: 100–125 PSI
• HazMat placard required when carrying over 1,001 lbs of hazardous material

How Many Times Can You Retake It?

Most states allow you to retake the CDL General Knowledge test multiple times, but impose a waiting period between attempts (usually 1–7 days). If you fail three times, some states require a longer wait (30 days) before you can test again. Check your specific state's rules.

The best strategy is simple: don't take the test until you're consistently scoring 85%+ on practice tests. Going in with a 75% average leaves too much to chance. Our practice test platform tracks your exact score and flags which sections need more work.

Tips for Passing on the First Try

• Take at least 5 full-length practice tests before the real exam
• Review every question you got wrong — understand the "why"
• Memorize the key numbers (PSI levels, stopping distances, following distances)
• Don't rush — the test isn't timed, so read carefully
• If you're unsure, eliminate the obviously wrong answers first