CDL General Knowledge Practice Test: What to Expect (2026)

The CDL general knowledge test is the first exam every commercial driver must pass, usually around 50 multiple-choice questions with a passing score of about 80%. It is a state test you take to earn your commercial learner's permit (CLP), and it is separate from the federally required Entry-Level Driver Training (ELDT) you complete later. If you need ELDT, RoadCert offers FMCSA-registered online ELDT theory for Class A, Class B, Hazmat and Passenger, and we report your completion to the FMCSA for you.

What does the test cover?

The questions come from your state's CDL manual and focus on the fundamentals: pre-trip and post-trip vehicle inspection, basic vehicle control, safe shifting, choosing a safe speed and following distance, space management on all sides of the vehicle, seeing hazards early, night and adverse-weather driving, and what to do in an emergency. You do not need endorsement-specific knowledge such as air brakes or hazmat for this test unless you are separately taking those exams.

How does it fit into getting your CDL?

1. Pass the general knowledge test (and any endorsement knowledge tests) to get your CLP (49 CFR 383.73).
2. Hold your CLP for the required waiting period, at least 14 days in most cases (49 CFR 383.25).
3. Complete ELDT theory and behind-the-wheel training from a registered provider.
4. Pass the CDL skills test to get your license.

A common mistake is confusing this knowledge test with training. The test proves you know the rules; ELDT proves you can operate the vehicle. Both are required, but at different stages (49 CFR 380.609).

Sample questions

Try these, then check the answers below.

1. When checking your tires during a pre-trip inspection, the minimum tread depth for front (steering) tires is generally:
   • a) 2/32 inch
   • b) 4/32 inch
   • c) 6/32 inch
   • d) 8/32 inch
2. You should use your low beams:
   • a) Only in the rain
   • b) When following or meeting another vehicle at night
   • c) Never on the highway
   • d) Only in tunnels
3. The safest way to stop on a slippery road is to:
   • a) Brake hard and fast
   • b) Brake gently and gradually
   • c) Downshift only
   • d) Pump the brakes rapidly
4. Total stopping distance is made up of:
   • a) Perception distance, reaction distance, and braking distance
   • b) Reaction distance only
   • c) Braking distance only
   • d) Following distance and speed
5. When driving in fog, you should:
   • a) Turn on your high beams
   • b) Speed up to get through it
   • c) Slow down and use low beams
   • d) Turn off your lights
6. The most important reason for doing a vehicle inspection is:
   • a) It is required by law and finds problems that could cause a crash
   • b) To pass time
   • c) To warm up the engine
   • d) To check the radio

Answers: 1) b, 4/32 inch on steering tires. 2) b. 3) b. 4) a. 5) c. 6) a.

How to study effectively

The general knowledge test rewards repetition in the real question format. Three steps work best:

1. Read your state's CDL manual cover to cover. Every question is drawn from it, and states differ slightly, so use your own state's manual.
2. Take practice tests until you are consistently scoring above 80%, not just once but repeatedly.
3. Focus your review on the categories you miss most, usually inspection details and stopping-distance concepts.

What comes next

Once you pass and get your permit, your next step is completing your ELDT theory, which you can do online through an FMCSA-registered provider for as little as $18.99. After the required waiting period and your training, you take the skills test for your CDL.

The bottom line

Expect about 50 questions, an 80% passing bar, and material straight from your state's CDL manual. Read the manual, drill practice tests until you are steadily above 80%, and you will pass the first exam on the path to your CDL.

Sources

Checked November 2, 2026.

• eCFR: 49 CFR 383.25, Commercial learner's permit (CLP): The general knowledge test earns your CLP, and you must hold the CLP at least 14 days before the skills test.
• eCFR: 49 CFR 383.73, State procedures: States administer the knowledge tests you must pass to obtain a CLP.
• eCFR: 49 CFR 380.609, General entry-level driver training requirements: ELDT is required in addition to the knowledge test, completed before the skills test or endorsement test.
• FMCSA: Entry-Level Driver Training (ELDT): ELDT is a separate, federally required training that new CDL applicants complete.
• FMCSA Training Provider Registry: ELDT theory and behind-the-wheel training must come from a provider listed on the FMCSA Training Provider Registry.