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Oklahoma CDL practice test

Getting a commercial driver's licence in Oklahoma starts with the CDL knowledge tests. The content is federal: every state, Oklahoma 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 Oklahoma driver licensing agency administers the test; the rules behind it are published by the FMCSA. Try the free Oklahoma CDL practice questions below, then pick a full test.

Free Oklahoma CDL practice questions

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

  1. A 'wig wag' low-pressure warning device:

    • Flashes the headlights when the brakes are hot
    • Sounds a horn when the tanks are full
    • Vibrates the brake pedal when ABS is active
    • Drops a mechanical arm into your view when air pressure falls below about 60 psi
    Show answer
    Answer: D. Drops a mechanical arm into your view when air pressure falls below about 60 psi

    The low air warning may be a red light, a buzzer, or a wig wag arm that swings down in front of you. On some vehicles the arm rises out of view only when pressure is above 60 psi.

    Source: FMCSA CDL Manual, Section 5.1.9 (Low Air Pressure Warning)

  2. The stop light switch in an air brake system is:

    • An electric switch worked by air pressure that turns on the brake lights when you apply the brakes
    • A switch you flip by hand to turn on the brake lights
    • A valve that limits pressure to the front brakes
    • A warning lamp that shows ABS faults
    Show answer
    Answer: A. An electric switch worked by air pressure that turns on the brake lights when you apply the brakes

    When air pressure goes to the brakes, it also closes the stop light switch, which lights the brake lamps. Drivers behind you need that warning when you slow down.

    Source: FMCSA CDL Manual, Section 5.1.10 (Stop Light Switch)

  3. Some older vehicles have a front brake limiting valve with a 'normal' and 'slippery' setting. How should it be used?

    • Set it to slippery whenever it rains
    • Set it to slippery on dry roads to save the front brakes
    • Leave it in the normal position; front-wheel braking is good under all conditions
    • Switch it off completely
    Show answer
    Answer: C. Leave it in the normal position; front-wheel braking is good under all conditions

    The slippery setting cuts normal air pressure to the front brakes by half. Tests showed front brakes do not cause skids even on ice, so cutting their power only makes your stopping distance longer.

    Source: FMCSA CDL Manual, Section 5.1.11 (Front Brake Limiting Valves)

  4. Spring brakes are held in the released position by:

    • Hydraulic pressure
    • An electric solenoid
    • The parking brake cable
    • Air pressure
    Show answer
    Answer: D. Air pressure

    Powerful springs apply the brakes; air pressure holds those springs back. When air pressure drops low enough, the springs take over and apply the brakes on their own.

    Source: FMCSA CDL Manual, Section 5.1.12 (Spring Brakes)

  5. The braking power of spring brakes depends on:

    • The service brakes being properly adjusted
    • The size of the air compressor
    • How full the fuel tank is
    • The speed of the vehicle
    Show answer
    Answer: A. The service brakes being properly adjusted

    Spring brakes use the same brake shoes and drums as the service brakes. If the brakes are out of adjustment, neither the service brakes nor the parking and emergency brakes will work properly.

    Source: FMCSA CDL Manual, Section 5.1.12 (Spring Brakes)

Every CDL test for Oklahoma drivers

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

How the Oklahoma 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 Oklahoma 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.

Oklahoma CDL test questions

How many questions are on the Oklahoma CDL test?

The Oklahoma 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 Oklahoma 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 Oklahoma?

At the Oklahoma 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 Oklahoma CDL practice questions?

Yes. Pick Oklahoma 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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