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South Carolina CDL practice test

Getting a commercial driver's licence in South Carolina starts with the CDL knowledge tests. The content is federal: every state, South Carolina included, writes its tests from the FMCSA CDL manual, so the general knowledge test has 50 questions, the endorsement tests have 20 to 30, and the passing score is 80% on each. The South Carolina driver licensing agency administers the test; the rules behind it are published by the FMCSA. Try the free South Carolina CDL practice questions below, then pick a full test.

Free South Carolina CDL practice questions

Five questions from the general knowledge, air brakes and combination vehicles banks, the three tests most South Carolina Class A applicants take first. Show the answer to read the explanation.

  1. During the static leakage test on a single vehicle (engine off, brakes released, after the initial pressure drop), the air loss in one minute should be no more than:

    • 3 psi
    • 4 psi
    • 2 psi
    • 6 psi
    Show answer
    Answer: C. 2 psi

    With a fully charged system, turn off the engine, release the service brake, and watch the gauge for a minute after the first drop. A single vehicle may lose up to 2 psi; a combination vehicle up to 3 psi.

    Source: FMCSA CDL Manual, Section 5.3.3 (Test Air Leakage Rate)

  2. During the static leakage test on a combination vehicle (engine off, brakes released), the one-minute air loss should be no more than:

    • 1 psi
    • 2 psi
    • 5 psi
    • 3 psi
    Show answer
    Answer: D. 3 psi

    A combination has more lines, couplings, and chambers, so the limit is a little higher: 3 psi per minute with the brakes released. A single vehicle gets 2 psi.

    Source: FMCSA CDL Manual, Section 5.3.3 (Test Air Leakage Rate)

  3. During the applied leakage test on a combination vehicle (engine off, service brake pedal held down), the air loss after the initial drop should be no more than:

    • 4 psi in one minute
    • 2 psi in one minute
    • 3 psi in one minute
    • 8 psi in one minute
    Show answer
    Answer: A. 4 psi in one minute

    Applying the brakes pressurizes more of the system, so the allowed loss rises: 3 psi per minute for a single vehicle and 4 psi per minute for a combination. More than that is a leak that must be fixed before driving.

    Source: FMCSA CDL Manual, Section 5.3.3 (Test Air Leakage Rate)

  4. When making a normal stop in a vehicle with air brakes and a manual transmission, you should:

    • Push in the clutch first, then brake
    • Push the pedal down steadily to stop smoothly, and not push in the clutch until engine rpm is close to idle
    • Shift to neutral and use the parking brake
    • Pump the pedal to get the best stop
    Show answer
    Answer: B. Push the pedal down steadily to stop smoothly, and not push in the clutch until engine rpm is close to idle

    Controlled, steady pedal pressure gives a smooth, safe stop. Keeping the clutch out until the engine is near idle lets the engine help slow the vehicle. When stopped, select a starting gear.

    Source: FMCSA CDL Manual, Section 5.4.1 (Normal Stops)

  5. When stab braking, you release the brakes as soon as the wheels lock. After release, the wheels may take how long to start rolling again?

    • About five seconds
    • They roll instantly
    • Up to one second
    • About half a minute
    Show answer
    Answer: C. Up to one second

    Stab braking means applying full brakes, releasing when the wheels lock, and reapplying as soon as the wheels roll. If you reapply before they are rolling, the vehicle will not straighten out.

    Source: FMCSA CDL Manual, Section 5.4.2 (Emergency Stops: Stab Braking)

Every CDL test for South Carolina drivers

Each page has ten free sample questions, the real question count, the 80% pass mark and what the test covers.

How the South Carolina CDL knowledge test works

You take the general knowledge test first; it is required for every CDL class. Class A drivers add the combination vehicles test. Almost everyone takes the air brakes test, because skipping it puts an air brake restriction on the licence. Endorsements (hazmat, tanker, doubles/triples, passenger, school bus) each have their own knowledge test. Pass the tests and you hold a commercial learner's permit; the skills test in a truck comes later.

Fees, appointment rules and test centre locations are set by South Carolina and change over time, so check the state driver licensing agency before you go. What does not change is the content, and that is what PassRig drills.

South Carolina CDL test questions

How many questions are on the South Carolina CDL test?

The South Carolina CDL general knowledge test follows the federal model: 50 questions, 40 correct to pass. Endorsement tests are shorter: air brakes 25, hazmat 30, and combination vehicles, tanker, doubles/triples, passenger and school bus 20 each.

What is the passing score on the South Carolina CDL permit test?

80% on every knowledge test, the same pass mark used across the United States.

Where do I take the CDL knowledge test in South Carolina?

At the South Carolina state driver licensing agency (the DMV, DOT or equivalent). Check its website for locations, appointments and current fees; the test content itself comes from the FMCSA CDL manual.

Does PassRig have South Carolina CDL practice questions?

Yes. Pick South Carolina in the app and you get practice sets and mock exams built from the knowledge test content your state uses, with the real counts and the 80% line.

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