New Jersey CDL Air Brakes Practice Test (NJ) 2

4.9 out of 5 (90 votes)
80% Passing score
20 Questions
4 Mistakes allowed
Prepare to ace your NJ CDL air brake endorsement with our comprehensive NJ CDL air brake practice test. This essential tool features 20 multiple-choice questions covering key topics such as air brake components, operational procedures, safety inspections, and stopping distance calculations. You'll delve into crucial details like dual air brake systems, which enhance safety by providing a backup if one system fails. To pass, you'll need to answer at least 16 questions correctly, ensuring you have the knowledge to operate safely and effectively on the road. In New Jersey, driving isn't just about knowing the rules-it's about navigating the unique challenges our roads present. From the bustling traffic of the Garden State Parkway to the tight turns of our suburban streets, understanding how to handle an air brake system is crucial. Our NJ DMV air brake test includes real-life scenarios that mimic these local driving conditions, helping you become not just a test-ready driver but a safer one on NJ's roads. While many practice tests come with a hefty price tag, our permit practice test is completely free. Despite being free, it rivals any paid counterpart in terms of features and study opportunities. Alongside the New Jersey DMV practice test, we recommend supplementing your study with the NJ driver's handbook, state-certified driver's education courses, flashcards, and road sign charts to cover all aspects of the NJ DMV permit test comprehensively. This New Jersey CDL air brake practice test is designed to ensure you're fully prepared for every aspect of the CDL test. Whether you're dealing with the unpredictable weather that often hits our state or navigating through densely populated urban areas, this test will help you master the necessary skills. With thorough preparation, you'll be ready to tackle the CDL air brake test and handle NJ's roads with confidence and competence.
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Sample New Jersey Air Brakes Test Questions

Question 1

During the applied air-leakage test on a single vehicle, what is the maximum acceptable pressure loss?

  1. A 3 psi in one minute
  2. B 2 psi in 45 seconds
  3. C 1 psi in one minute
  4. D 1 psi in 30 seconds

Correct answer: A – 3 psi in one minute

The New Jersey CDL manual allows no more than 3 psi of pressure loss in one minute for a single vehicle during the applied leakage test. The engine is shut off, the parking brake is released, and the foot brake is held fully applied. A loss greater than 3 psi indicates excessive leakage that must be repaired before driving.

Source: New Jersey Commercial Driver License Manual — § 5.3.3, “Step 7 Final Air Brake Check”

Question 2

Why do air brakes take longer to apply than hydraulic brakes?

  1. A Their brake drums rotate more slowly
  2. B Compressed air must travel through the lines to the brakes
  3. C Their return springs must be released first
  4. D The spring brakes oppose every service-brake application

Correct answer: B – Compressed air must travel through the lines to the brakes

Air-brake operation includes a delay between pressing the pedal and applying the brakes. Compressed air must move through the lines to the brake chambers, a process that can take one-half second or more. This brake lag adds to the vehicle’s total stopping distance.

Source: New Jersey Commercial Driver License Manual — § 5.4.4, “Stopping Distance”

Question 3

Why must you select the proper low gear before descending a long, steep grade?

  1. A To use engine braking as the principal method of controlling speed
  2. B To make shifting easier after the vehicle gains speed
  3. C To keep air pressure above governor cut-out
  4. D To reduce wear on the steering system

Correct answer: A – To use engine braking as the principal method of controlling speed

Select a low gear before starting down the grade because engine braking should be the principal way to control speed. Once speed has built up, you may be unable to shift into a lower gear and could lose the engine-braking effect. Service brakes should remain available for controlled slowing or stopping as conditions require.

Source: New Jersey Commercial Driver License Manual — § 2.16.2, “Select the Right Gear before Starting Down the Grade”, New Jersey Commercial Driver License Manual — § 2.16.4, “Proper Braking Technique”

Question 4

What are the two parts of a dual air-brake system called?

  1. A Primary and secondary
  2. B Service and parking

Correct answer: A – Primary and secondary

A dual air-brake system contains two separate systems operated through one set of controls. One is called the primary system, and the other is the secondary system. The New Jersey CDL manual instructs drivers to build sufficient pressure in both systems before driving.

Source: New Jersey Commercial Driver License Manual — § 5.2, “Dual Air Brake”

Question 5

Which braking method should be used on a long, steep downgrade?

  1. A Wait until you exceed the safe speed by 5 mph before braking
  2. B Use only the trailer hand valve to control speed
  3. C Keep light, continuous pressure on the brake pedal
  4. D Use engine braking, apply the brakes at the safe speed, and release them about 5 mph below it

Correct answer: D – Use engine braking, apply the brakes at the safe speed, and release them about 5 mph below it

First select the proper low gear and use the engine-braking effect. When the vehicle reaches its safe speed, apply the brakes firmly enough to produce a definite slowdown. Release them when speed is approximately 5 mph below the safe speed, then repeat the procedure when the vehicle returns to that speed.

Source: New Jersey Commercial Driver License Manual — § 5.4.6, “Proper Braking Technique”

Question 6

An alcohol evaporator removes moisture from an air-brake system by condensing it.

  1. A TRUE
  2. B FALSE

Correct answer: B – FALSE

An alcohol evaporator introduces alcohol into the air system; it does not condense the air or remove collected water. The alcohol reduces the risk of ice forming in valves and other components during cold weather. Air tanks must still be drained as required to remove water and oil.

Source: New Jersey Commercial Driver License Manual — § 5.1.5, “Alcohol Evaporator”

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