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Free District of Columbia CDL Combination Vehicles Practice Test 2023

You have to pass the CDL combination vehicles endorsement to get ready for propelling your career with your license. You are looking for a good DC CDL practice test source for your coming CDL test? You are in the right place. Our practice test is a great resource for beginners. The CDL practice test is designed for you to have exactly the experience of the exam as you will be more familiar with both the test format and the subject. They cover topics ranging from combination vehicle maintenance to safely driving a complex rig. Each question is based on the official DC CDL Manual so you can be sure that the information in our test is accurate and relevant to your examination. In addition, each question has a detailed explanation so that it is very useful for you to learn from your mistakes. Preparing well before test day with questions and content that we cover. Start with our Free District of Columbia CDL Combination Vehicles Practice Test today and walk out with your endorsement!

Our CDL practice tests:
Based on 2021 DC commercial driver's license manual
Full answers + detailed explanations
Perfect for first-time, renewal applicants
DC CDL Combination Vehicles Test format:
20 questions
16 correct answers to pass
80% passing score
Study now
List of questions
1.
Air brake equipped trailers made before 1975:
2.
To prevent moisture from entering the electrical cable when disconnected:
3.
One good way to prevent rollover is:
4.
When inspecting the coupling area, all of the following are required except:
5.
While driving behind another vehicle, under good conditions, you should allow at least one second between your vehicle and the vehicle ahead for each ____ feet of your vehicle length.
6.
To unlock the fifth wheel, the locking lever should be placed in the ______ position.
7.
The iron trailer supports are up and the trailer is resting on the tractor. Make sure:
8.
The tractor protection valve will close, and the trailer emergency brakes will come on when there is a major leak in the _____ brake line.
9.
Supplied by the service line from the tractor, each trailer or dolly has its own:
10.
When you are uncoupling a loaded trailer, you should lower the landing gear until it:
11.
In order to allow the trailer brakes to be applied more quickly, what is connected to the service air line?
12.
When unlocking the fifth wheel in Step 6, all of the following apply except:
13.
Trailers will have an ABS malfunction lamp:
14.
When uncoupling, the tractor should:
15.
Trailer landing gear:
16.
Crack-the-whip effect occurs when:
17.
When coupling or uncoupling, all of these apply to the trailer except:
18.
To test the trailer brakes before driving, use the hand valve or the:
19.
What will happen if the air lines are crossed when you hook up to an old trailer?
20.
When uncoupling the trailer, after you shut off the trailer air supply and lock the trailer brakes, you should:
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