Virginia CDL Combination Practice Test (VA) 2

5 out of 5 (64 votes)
80% Passing score
20 Questions
4 Mistakes allowed
Preparing for the VA CDL combination practice test on our website is a vital step towards mastering the skills needed to handle a commercial vehicle in Virginia's diverse driving environments. From the bustling highways of Northern Virginia to the winding rural roads in the Shenandoah Valley, each region presents unique challenges that require specific driving skills and knowledge. Our VA DMV permit practice test is designed to enhance your understanding of critical aspects such as inspection procedures, safe driving practices, and air brake systems. With 20 multiple-choice questions, this test covers everything from basic controls to the risks of jackknifing, where the trailer swings out from alignment with the tractor. It's crucial to know how to manage such situations through smooth braking and cautious handling, ensuring your safety and that of other road users. To aid your learning, many questions are accompanied by visual aids, illuminating complex concepts and catering especially to visual learners. After completing the combination vehicle test, you'll receive a summary of your performance. This includes a detailed review of the questions you missed, complete with correct answers and explanations, allowing you to learn from your mistakes and better prepare for the actual permit test. Moreover, you can revisit your answers and the provided hints and explanations at any time, ensuring that you fully grasp the material and improve on subsequent attempts. This approach not only prepares you for the permit test but also instills the knowledge and confidence required for long-term success in your driving career.
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Sample Virginia Combination Test Questions

Question 1

How should you confirm that a tractor and semitrailer are securely coupled?

  1. A. Pull forward with a sharp jerk in a high gear
  2. B. Rock the trailer sideways with its brakes released
  3. C. Pull gently forward in low gear against the locked trailer brakes, then inspect the coupling
  4. D. Assume the connection is secure if the kingpin made contact

Correct answer: C. – Pull gently forward in low gear against the locked trailer brakes, then inspect the coupling

The Virginia coupling procedure calls for raising the landing gear slightly and pulling the tractor gently forward while the trailer brakes remain locked. This confirms that the trailer is held by the fifth wheel. The driver must then visually inspect the jaws, kingpin, locking lever, safety latch, and the space between the fifth-wheel plates.

Source: Virginia Commercial Driver’s Manual — § 6.4.1, “Coupling Tractor-Semitrailers”

Question 2

Which component allows trailer brakes to apply quickly by using air stored in the trailer tanks?

  1. A. Quick-release valve
  2. B. Relay valve
  3. C. Front-wheel limiting valve
  4. D. Tractor protection valve

Correct answer: B. – Relay valve

The service air line is connected to relay valves. Service-line pressure tells the relay valves how much air pressure to send from the trailer tanks to the brakes. Using nearby stored air allows the trailer brakes to apply more quickly than sending operating air all the way from the tractor.

Source: Virginia Commercial Driver’s Manual — § 6.2.4, “Trailer Air-lines”; § 6.2.6, “Trailer Air Tanks”

Question 3

What damage may occur if a semitrailer is positioned too low during coupling?

  1. A. The trailer may not release its spring brakes
  2. B. The air lines may become impossible to connect
  3. C. The tractor may strike and damage the trailer nose
  4. D. No damage can occur because the trailer will always rise

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

A properly positioned trailer should be raised slightly as the tractor backs beneath it. If the trailer is set too low, the tractor can strike and damage the trailer nose instead of sliding correctly under the upper coupling surface. Raise the trailer with the landing gear before continuing the coupling procedure.

Source: Virginia Commercial Driver’s Manual — § 6.4.1, “Coupling Tractor-Semitrailers”

Question 4

What can happen if the emergency air line separates and loses pressure while a combination vehicle is moving?

  1. A. Only the tractor’s service brakes stop working
  2. B. The trailer air tanks automatically refill
  3. C. The relay valve keeps the damaged line pressurized
  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

Loss of pressure in the emergency, or supply, line causes the trailer emergency brakes to apply. It also closes the tractor protection valve, preventing the trailer leak from draining all air from the tractor. A separated service line does not automatically produce the same immediate result unless the resulting air loss lowers system pressure sufficiently.

Source: Virginia Commercial Driver’s Manual — § 6.2.4, “Trailer Air-lines”; § 6.2.8, “Trailer Service, Parking and Emergency Brakes”

Question 5

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

  1. A. The helper can watch blind spots the driver cannot see
  2. B. The helper can make the vehicle back 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 watch blind spots the driver cannot see

The Virginia CDL manual recommends using a helper whenever possible because the driver cannot see every area behind the vehicle. The helper should remain near the rear where the driver can see them. Before backing, the driver and helper should agree on clear hand signals, including a signal requiring an immediate stop.

Source: Virginia Commercial Driver’s Manual — § 2.2.4, “Backing Safely”

Question 6

What is the function of a combination vehicle’s service air line?

  1. A. It supplies air directly to the trailer parking brakes
  2. B. It sends cooling air into the tractor cab
  3. C. It carries brake-control pressure to the trailer relay valves
  4. D. It continuously fills the trailer air tanks

Correct answer: C. – It carries brake-control pressure to the trailer relay valves

The service line is also called the control or signal line. Its pressure changes according to foot-brake or trailer hand-valve input and tells the relay valves how strongly to apply the trailer brakes. The emergency, or supply, line performs the separate job of filling the trailer air tanks.

Source: Virginia Commercial Driver’s Manual — § 6.2.4, “Trailer Air-lines”

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