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Iowa CDL Practice Test: Double and Triples - Test 2 2020

(From the 2020 Iowa CDL Handbook)
Number of tests: 25
Number of questions: 30
Passing score: 80

Directions: To obtain this endorsement for pulling two or three trailers, applicants must pass a 15-question test. And to pass the test, applicants must score at least 80%. Test questions are from the Iowa Commercial Driver Handbook. The Double/Triple trailers endorsement can be used with the Class A CDL. If you need additional information, please contact your local DMV office. You can find your nearest DMV office at Iowa DMV locations.

1. Why should you never push the brake pedal down when the spring brakes are on?

2. The tractor protection valve ______.

3. What are hose couplers?

4. You should check the height of the trailer before connecting a converter dolly to a second or third trailer. The trailer height is right when _____.

5. If you are coupling twin trailers, you should release the dolly brakes by ______.

6. When turning wide, keeping the rear of your long vehicle close to the curb will ________.

7. You are testing the stopping action of service brakes on a hydraulic system. Which of the following may indicate that there is a problem with your service brakes?

8. When connecting the converter dolly to the rear trailer, you should remember to ________.

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