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New Jersey CDL practice test

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

Free New Jersey CDL practice questions

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

  1. An air brake system is really three braking systems combined. They are the:

    • Service, parking and emergency brakes
    • Drum, disc and wedge brakes
    • Foot, hand and engine brakes
    • Primary, secondary and trailer brakes
    Show answer
    Answer: A. Service, parking and emergency brakes

    The service brakes stop you when you press the pedal, the parking brakes hold the vehicle with spring pressure, and the emergency brakes use parts of both to stop you if air is lost.

    Source: FMCSA CDL Manual, Section 5.1 (The Parts of an Air Brake System)

  2. The air compressor governor stops the compressor pumping ("cut-out") at about:

    • 60 psi
    • 100 psi
    • 125 psi
    • 150 psi
    Show answer
    Answer: C. 125 psi

    The governor cuts the compressor out around 125 psi and cuts it back in around 100 psi. When you test the governor, pressure should fall to about 100 psi with brake applications and then start building again.

    Source: FMCSA CDL Manual, Section 5.1.2 (Air Compressor Governor)

  3. The low air pressure warning must come on before pressure drops below:

    • 20 psi
    • 45 psi
    • 60 psi
    • 100 psi
    Show answer
    Answer: C. 60 psi

    By 60 psi you must have a light, a buzzer or a wig-wag warning you. Below that, you have very little usable brake left, so stop safely as soon as you can and fix the problem.

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

  4. Spring brakes usually apply by themselves when air pressure falls to about:

    • 5 to 10 psi
    • 20 to 45 psi
    • 60 to 80 psi
    • 100 to 125 psi
    Show answer
    Answer: B. 20 to 45 psi

    Powerful springs hold the brakes on; air pressure holds them off. Once pressure drops into the 20 to 45 psi range, the springs win and the brakes come on fully, whether you want them to or not.

    Source: FMCSA CDL Manual, Section 5.1.14 (Spring Brakes)

  5. Why should you drain the air tanks every day?

    • To raise the cut-in pressure
    • To remove water and compressor oil that collect in the tanks and can freeze or damage the brakes
    • To reset the low pressure warning
    • To keep the compressor from running too often
    Show answer
    Answer: B. To remove water and compressor oil that collect in the tanks and can freeze or damage the brakes

    Compressed air carries moisture and a little compressor oil. Both settle in the tanks; water can freeze in cold weather and stop the brakes working. Open the drain valves at the end of each day until no more water comes out.

    Source: FMCSA CDL Manual, Section 5.1.3 (Air Storage Tanks and Tank Drains)

Every CDL test for New Jersey drivers

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

How the New Jersey 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 New Jersey 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.

New Jersey CDL test questions

How many questions are on the New Jersey CDL test?

The New Jersey 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 New Jersey 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 New Jersey?

At the New Jersey 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 New Jersey CDL practice questions?

Yes. Pick New Jersey 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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