Oregon CDL Combination Test (OR) 2026

5 out of 5 (57 votes)
80% Passing score
20 Questions
4 Mistakes allowed
Preparing for the Oregon CDL combination test is an essential step for aspiring commercial drivers. This Oregon CDL combination test is designed to equip you with the knowledge and skills necessary to safely operate combination vehicles, such as tractor-trailers. With a focus on key areas, the Oregon DMV permit practice test ensures you're well-prepared to handle the challenges of the road. The Oregon DMV practice test consists of 20 carefully crafted multiple-choice questions. These questions cover crucial topics like coupling and uncoupling procedures, pre-trip inspections, and air brake systems. Understanding the increased stopping distances required for combination vehicles is vital. Due to their greater weight, combination vehicles present unique challenges, making it crucial to master these concepts for safety and efficiency on the road. An outstanding feature of this Oregon CDL combination test is the immediate feedback provided after each question. This instant feedback, along with detailed explanations, helps you understand why a particular answer is correct or incorrect. Such insights are invaluable for reinforcing your understanding of the material and correcting misconceptions. Once you complete the Oregon driver's permit practice test, you have the opportunity to review your answers. This review process includes revisiting questions you might have missed, along with hints and explanations. This is an excellent way to consolidate your knowledge and identify areas that may need further attention. Additionally, the Oregon DMV practice test offers an end-of-test summary. This summary highlights the questions you answered incorrectly, providing the correct answers for each. This comprehensive review ensures you leave the practice permit test with a clear understanding of your performance and areas for improvement. By using the Oregon combination CDL test, you're setting the stage for success in your commercial driving career. With thorough preparation and understanding, you'll be ready to navigate the roads safely and confidently, equipped with the skills needed to operate combination vehicles responsibly.
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Sample Oregon Combination Test Questions

Question 1

Why should glad-hand couplers and seals be inspected and cleaned before the air lines are connected?

  1. A To reduce tire wear
  2. B To improve fuel economy
  3. C To change the trailer’s ride height
  4. D To help prevent air from escaping at the connection

Correct answer: D – To help prevent air from escaping at the connection

Glad hands connect the tractor’s service and emergency air lines to the trailer. Their rubber seals prevent air from escaping, so the couplers and seals should be clean and in suitable condition before connection. The matching couplers must be pressed together and turned until they join and lock securely.

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

Question 2

What is the main safety benefit of using a helper when backing a trailer?

  1. A The helper can warn you about hazards in blind spots and provide guidance
  2. B The helper can make the tractor move faster
  3. C The helper can operate the trailer brakes from outside
  4. D The helper can adjust the mirrors while the vehicle moves

Correct answer: A – The helper can warn you about hazards in blind spots and provide guidance

Oregon’s CDL manual recommends using a helper whenever possible because the driver cannot see every area behind the vehicle. The helper should stand near the rear where the driver can still see them. Before backing begins, both people should agree on understandable hand signals, especially a signal requiring the driver to stop.

Source: Oregon Commercial Driver Manual — § 2.2.4, “Backing Safely”

Question 3

After coupling a tractor and semitrailer, where must the fifth-wheel locking jaws be positioned?

  1. A Around the shank of the kingpin
  2. B Around the head of the kingpin
  3. C Above the kingpin base
  4. D Against the trailer’s landing gear

Correct answer: A – Around the shank of the kingpin

During the coupling inspection, look into the rear of the fifth wheel and confirm that the jaws have closed around the kingpin’s shank. There should be no visible space between the upper and lower fifth wheel. The locking lever and safety latch must also be in their secured positions before the vehicle is driven.

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

Question 4

What problem may result if the fifth-wheel plate is not lubricated as required?

  1. A Steering difficulty caused by excessive friction
  2. B Loss of pressure from the trailer air tanks
  3. C Automatic lowering of the landing gear
  4. D Failure of the trailer brake lights

Correct answer: A – Steering difficulty caused by excessive friction

The fifth-wheel plate must be greased as required before coupling. Without proper lubrication, friction develops between the tractor and trailer as the combination turns. That friction can interfere with steering and make the vehicle more difficult to control.

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

Question 5

What happens if the emergency air line separates while a combination vehicle is moving?

  1. A The tractor’s service brakes immediately stop working
  2. B Only the trailer brake lights are affected
  3. C Nothing changes until the brake pedal is pressed
  4. D The trailer emergency brakes apply and the tractor protection valve closes

Correct answer: D – The trailer emergency brakes apply and the tractor protection valve closes

Oregon’s CDL manual states that loss of pressure in the emergency, or supply, line causes the trailer emergency brakes to apply. The pressure loss also closes the tractor protection valve, stopping air from escaping from the tractor. The trailer air-supply control may pop out when this occurs.

Source: Oregon Commercial Driver Manual — § 6.2.4, “Trailer Air-lines”

Question 6

How often should each trailer air tank be drained?

  1. A Once each week
  2. B Every day
  3. C Once each month
  4. D Only after a brake problem develops

Correct answer: B – Every day

Water and oil must not be allowed to build up in trailer air tanks because contamination can interfere with brake operation. Each tank should be drained every day. Even when automatic drains are installed, the manual directs drivers to open the drains to verify that moisture is being removed.

Source: Oregon Commercial Driver Manual — § 6.2.6, “Trailer Air Tanks”

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