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CDL Combination Vehicles – General Knowledge Flashcards

Master the essential concepts of combination vehicles for your CDL General Knowledge exam. These 25 flashcards cover coupling and uncoupling procedures, air brakes on combinations, rollover prevention, and safe driving techniques for tractor-trailers and doubles. Ideal for first-time CDL applicants and drivers upgrading their license class.

25 cards Intermediate Coupling & Uncoupling Air Brakes on Combination Vehicles Rollover Prevention Safe Driving Techniques Vehicle Inspection – Combination Vehicles

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Preview Questions

Question 1

Before backing a tractor under a trailer during coupling, what must you do to the trailer brakes?

Answer

Apply the trailer brakes (emergency/supply valve) to hold the trailer in place while you back under it.

Question 2

After coupling, how do you test that the fifth wheel has locked correctly?

Answer

Pull the tractor gently forward while the trailer brakes are still applied (or parking brake set) and feel for resistance, confirming the locking jaws are secured around the kingpin.

Question 3

What is the correct height of a trailer nose when coupling a tractor to it?

Answer

The trailer should be low enough that it will be raised slightly when the tractor backs under it, meaning the trailer nose should be just below the height of the fifth wheel.

Question 4

When uncoupling a trailer, what should you do BEFORE lowering the landing gear completely?

Answer

Make sure the ground is firm enough to support the trailer's weight; if not, place planks or blocks under the landing gear.

Question 5

What color is the emergency (supply) air line glad hand on a combination vehicle?

Answer

Red – the emergency (supply) air line glad hand is red.

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