Colorado CDL Combination Practice Test (CO) 2

5 out of 5 (67 votes)
80% Passing score
20 Questions
4 Mistakes allowed
Driving in Colorado presents unique challenges, from navigating the steep mountain passes of the Rockies to dealing with sudden weather changes on the eastern plains. Preparing for these conditions requires thorough knowledge and skill, especially for commercial drivers handling combination vehicles. Our Colorado CDL combination practice test is specifically designed to enhance your readiness for the real thing. With 20 meticulously crafted multiple-choice questions, this Colorado permit practice test covers key topics such as inspection procedures, safe driving practices, and the critical aspects of air brake systems. To pass this CDL combination test, you need to correctly answer at least 16 out of the 20 questions. This Colorado practice permit test not only builds your confidence but also ensures you are well-prepared to tackle the challenges of the Colorado DMV practice test. One of the vital areas covered is the risk of jackknifing, a dangerous situation where the trailer swings out of alignment with the tractor. Through our detailed questions, you will learn essential techniques to avoid jackknifing, focusing on smooth braking and careful handling - skills crucial for safe driving on Colorado's diverse roads. After completing the Colorado CDL combination practice test, you will receive a comprehensive summary of your performance. This summary highlights the questions you answered incorrectly and provides the correct answers for your review, enabling you to learn and improve. Our driving test practice is crafted to mirror the actual DMV permit test experience closely, covering identical topics and designed with similar phrasing. This authentic practice experience helps you grasp the essential concepts necessary for passing your permit test. Remember, passing the combination CDL test is just one step in obtaining your commercial driver's license. You must also pass the general knowledge test, and we offer a variety of prep tests to help you succeed. Whether you're navigating the high-altitude roads of the Rockies or the flat expanses of the eastern plains, our Colorado CDL combination practice test will prepare you for the unique driving conditions you'll encounter across the state.
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Sample Colorado Combination Test Questions

Question 1

What does off-tracking describe?

  1. A The tractor leaving the pavement while completing a turn
  2. B The trailer reversing direction in the middle of a curve
  3. C The rear wheels following a different path from the front wheels
  4. D Operating a combination vehicle on an unpaved road

Correct answer: C – The rear wheels following a different path from the front wheels

Off-tracking occurs because the rear wheels follow a different path from the front wheels when a vehicle turns. The rear wheels of a tractor off-track, and a trailer's rear wheels off-track even more. Longer combinations have a greater effect, with the last trailer's rear wheels generally tracking farthest inside the front-wheel path.

Source: Commercial Driver License Manual — § 6.1.6, “Turn Wide”

Question 2

What can happen if a semitrailer is set too low before the tractor backs underneath it?

  1. A The fifth wheel will pass beneath the kingpin without locking
  2. B The glad hands cannot be connected
  3. C The tractor may strike and damage the trailer nose
  4. D The trailer will automatically rise without risk of damage

Correct answer: C – The tractor may strike and damage the trailer nose

Colorado's CDL manual states that a trailer set too low may be struck by the tractor, damaging the trailer nose. The proper height allows the tractor to raise the trailer slightly as it backs under it. By contrast, a trailer that is too high may fail to couple correctly with the fifth wheel.

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

Question 3

Before backing the tractor fully under a semitrailer, the trailer is at the proper height when:

  1. A The fifth wheel will pass completely below the kingpin
  2. B The kingpin is more than an inch above the fifth wheel
  3. C The bottom of the kingpin is level with the fifth-wheel plate
  4. D The tractor will raise the trailer slightly as it backs underneath

Correct answer: D – The tractor will raise the trailer slightly as it backs underneath

The semitrailer should be low enough that the tractor raises it slightly while backing underneath. Adjust the landing gear if necessary and confirm that the kingpin and fifth wheel are aligned. A trailer that is too high may not couple correctly, while one that is too low can be struck and damaged by the tractor.

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

Question 4

Which procedure correctly tests a trailer's emergency brakes?

  1. A Open both rear shutoff valves and leave them open
  2. B Charge the trailer system, pull out the trailer air-supply control, and gently pull against the trailer
  3. C Turn off the engine and repeatedly press the foot brake
  4. D Release all brakes and move forward without using the trailer air-supply control

Correct answer: B – Charge the trailer system, pull out the trailer air-supply control, and gently pull against the trailer

First charge the trailer air-brake system and verify that the trailer can roll freely. Stop, pull out the trailer air-supply control or place the tractor protection valve control in the emergency position. Pull gently on the trailer with the tractor; resistance confirms that the trailer emergency brakes have applied.

Source: Commercial Driver License Manual — § 6.5.2, “Combination Vehicle Brake Check”

Question 5

An inspection shows that the service and emergency air lines were crossed during coupling. What must the driver do?

  1. A Accelerate to build pressure faster
  2. B Continue if the tractor brakes operate
  3. C Compensate by using the trailer hand valve
  4. D Reconnect the lines correctly and test the trailer brakes

Correct answer: D – Reconnect the lines correctly and test the trailer brakes

Crossed air lines can keep supply air from charging the trailer tanks and releasing the trailer spring brakes. With some older trailers, the combination might move even though the trailer has no working brakes. Correct the glad-hand connections before driving, then test the trailer brakes by gently pulling against them in a low gear.

Source: Commercial Driver License Manual — § 6.2.5, “Hose Couplers (Glad Hands)”

Question 6

Before backing the tractor fully under a semitrailer during coupling, the air system should be:

  1. A Between 60 and 80 psi
  2. B Reduced to half of normal pressure
  3. C At normal operating pressure
  4. D Completely empty

Correct answer: C – At normal operating pressure

After connecting the service and emergency air lines, supply air to the trailer and wait for normal pressure. Check for crossed lines, major air loss, and proper trailer-brake operation. Restore normal pressure again, apply the trailer brakes with the air-supply control, and only then back the tractor slowly under the trailer.

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

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