Combination

All applicants who are applying for a Class A CDL should be prepared to take the Combination test. This test covers information found in Section 6 of the Connecticut Commercial Driver License..

All applicants who are applying for a Class A CDL should be prepared to take the Combination test. This test covers information found in Section 6 of the Connecticut Commercial Driver License Manual. Section 6 provides the information needed to safely operate tractor-trailers, doubles, triples, and straight trucks with trailers. The test is made up of 20 multiple-choice questions, and applicants will need to correctly answer a minimum of 16 questions to pass. The Combination test is not a replacement for the Double/Triple endorsement test.

Number of Question
Passing Score

8. Before backing your tractor under the trailer, make sure your trailer brakes are:

Explanation
Correctly following the steps to couple and uncouple trailers is vital to safely operating a combination vehicle. Before backing your tractor under the trailer while coupling, make sure your trailer brakes are locked.

9. Which of the following types of vehicles is most prone to the “crack-the-whip" effect?

Explanation
Double and triple combinations are the most vulnerable to turning over as a result of the "crack-the-whip" effect.

10. The "crack-the-whip" effect can:

Explanation
Trailers can overturn as a result of the "crack-the-whip" effect. The last trailer in a combination is the most prone to tip over due to this effect. Drivers should be aware of the rearward amplification of their specific vehicles and drive accordingly.

11. How much space should be between the upper and lower fifth wheel?

Explanation
Before a trip, be sure to inspect all couplings. There should be no space between the upper and lower fifth wheel.

12. Keeping cargo low can:

Explanation
Rollovers can happen when a combination vehicle is turned too quickly. To help prevent the risk of rollover, it is important to keep the vehicle's center of gravity low by loading cargo as close to the ground as possible.

13. Operating combination vehicles usually requires ­­­­­____ operating single vehicles.

Explanation
Combination vehicles are usually heavier and longer than single combination vehicles. Operating a combination vehicle requires a higher level of driving skill than operating a single commercial vehicle.

14. The trailer hand valve should be used:

Explanation
The trailer hand valve, also called the trolley valve or Johnson bar, is used to work the trailer brakes. It should be used only to test the brakes.