New Jersey CDL Combination Practice Test (NJ) 2

5 out of 5 (59 votes)
80% Passing score
20 Questions
4 Mistakes allowed
Boost your CDL preparation with our second NJ combination CDL practice test, tailored to help you ace your permit test. This knowledge test practice features 20 carefully selected multiple-choice questions that cover essential topics like inspection procedures, safe driving practices, and air brake systems. To pass, you'll need to answer at least 16 questions correctly. Real-life scenarios are a significant part of this NJ DMV practice test, immersing you in situations you might face on the road. For example, navigating the congested streets of Newark or handling tricky winter conditions in the Pine Barrens. Understanding these unique driving conditions will make you not only test-ready but also a safer, more competent driver. Our CDL combination practice test focuses on specifics, with questions that appear directly on the New Jersey permit practice test for this endorsement. This targeted approach ensures that you're studying the right material, helping you to avoid the risks associated with jackknifing. Mastering the skills of smooth braking and careful handling is crucial for preventing your trailer from swinging out of alignment with the tractor. This NJ combination vehicle test helps you pinpoint any lapses in your knowledge. Repeatedly taking the practice permit test will allow you to address these gaps and boost your confidence. Remember, obtaining your CDL requires passing the general knowledge test as well. If you need to brush up on that, we have additional general knowledge prep tests available to support your overall CDL preparation. Whether you're driving through the busy intersections of Jersey City or the scenic routes of the Delaware Water Gap, being well-prepared is essential. Our NJ combination CDL practice test is your key to mastering the combination CDL test and securing your CDL permit. Take advantage of this valuable resource and ensure you're ready for the challenges ahead.
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Sample New Jersey Combination Test Questions

Question 1

Which condition must you verify when inspecting the trailer air lines?

  1. A They are connected, leak-free, secured, and have enough slack for turns
  2. B They are stretched tightly between the tractor and trailer
  3. C They rest against the tractor frame during turns
  4. D They are disconnected whenever the electrical cord is plugged in

Correct answer: A – They are connected, leak-free, secured, and have enough slack for turns

Trailer air lines should be properly connected to the glad hands, free of leaks and damage, and correctly supported. They must have enough slack to permit turns without being stretched or pulled loose. Excessive slack should not be allowed to contact moving vehicle parts.

Source: New Jersey Commercial Driver License Manual — § 6.5.1, “Additional Things to Check during a Walk-around Inspection”

Question 2

How should you test the trailer emergency brakes?

  1. A Open both shut-off valves at the rear of the last trailer
  2. B Pull out the trailer air-supply control, then gently pull against the trailer
  3. C Turn off the engine and repeatedly press the brake pedal
  4. D Release all parking brakes and move forward at normal speed

Correct answer: B – Pull out the trailer air-supply control, then gently pull against the trailer

Charge the trailer air system and first verify that the trailer rolls freely. Stop, pull out the trailer air-supply control or place it in the emergency position, and gently pull forward with the tractor. The trailer should resist movement, showing that its emergency brakes are applied under the New Jersey manual’s inspection procedure.

Source: New Jersey Commercial Driver License Manual — § 6.5, “Inspecting a Combination Vehicle”

Question 3

What are the two functions of the trailer emergency air line?

  1. A Improving fuel economy and releasing the fifth wheel
  2. B Cooling the brakes and reducing tire wear
  3. C Supplying the trailer air tanks and controlling the emergency brakes
  4. D Operating the electrical system and landing gear

Correct answer: C – Supplying the trailer air tanks and controlling the emergency brakes

The emergency or supply line carries air from the tractor to the trailer air tanks. It also controls the trailer emergency brakes. A loss of pressure in this line causes the emergency brakes to apply and causes the tractor protection valve to close.

Source: New Jersey Commercial Driver License Manual — § 6.2.4, “Trailer Air-lines”

Question 4

Compared with an empty rig, a fully loaded rig is ten times more likely to roll over in a crash.

  1. A TRUE
  2. B FALSE

Correct answer: A – TRUE

A fully loaded rig is ten times more likely to roll over in a crash than an empty rig. As cargo is piled higher, the vehicle’s center of gravity rises and the rig becomes easier to overturn. Keep cargo low and centered, and reduce speed before curves and turns.

Source: New Jersey Commercial Driver License Manual — § 6.1.1, “Rollover Risks”

Question 5

What should you do if the trailer is too high for correct fifth-wheel coupling?

  1. A Raise the trailer farther
  2. B Back under it at a higher speed
  3. C Approach the kingpin at an angle
  4. D Lower the trailer to the proper coupling height

Correct answer: D – Lower the trailer to the proper coupling height

Lower the trailer until it is positioned so the tractor will raise it slightly while backing underneath. If the trailer is too high, the kingpin may not couple correctly with the fifth wheel. If it is too low, the tractor may strike and damage the trailer nose.

Source: New Jersey Commercial Driver License Manual — § 6.4.1, “Coupling Tractor-Semitrailers”

Question 6

If the trailer service air line separates but the emergency line remains connected, what will you probably notice first?

  1. A The tractor’s emergency brakes will apply immediately
  2. B The entire combination will stop immediately
  3. C The trailer tank will instantly empty through the emergency line
  4. D Nothing may be apparent until you apply the brakes

Correct answer: D – Nothing may be apparent until you apply the brakes

A major service-line leak may not be noticed until the driver applies the brakes. When a brake application sends air through the damaged line, pressure can fall rapidly and trailer service braking will be lost. If trailer pressure drops far enough, the trailer emergency brakes will apply.

Source: New Jersey Commercial Driver License Manual — § 6.2.8, “Trailer Service, Parking and Emergency Brakes”

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