Delaware Driver’s Examination

Combination

Number of Question
Passing Score

When backing up while coupling a trailer, the tractor should be positioned:

Explanation
When backing up to couple a trailer, you should position the tractor directly in front of the trailer. Trying to couple while backing at an angle could cause the trailer to move and the landing gear to break.

The ____ trailer is the most likely to turn over if a driver takes a turn too quickly.

Explanation
When making a turn, be sure to steer gently and smoothly. Making a quick turn while pulling trailers is dangerous and can increase the risk of the last trailer rolling over.

A shut-off valve:

Explanation
Shut-off valves are used in air supply lines to control the passage of air from one trailer to another. The rear shut-off valve should always be closed to prevent air from leaving the braking system.

Using the trailer hand brake while experiencing a trailer jackknife will:

Explanation
If you are experiencing a trailer jackknife, you can help your tires regain traction by releasing the brakes. Using a trailer hand brake while experiencing a skid will only cause the skid to continue.

If oil and water build up in your vehicle's air tanks, the brakes:

Explanation
Air tanks should be drained daily to remove water and oil buildup. An excess of oil and water in the air tanks can interfere with proper brake function.

Proper coupling technique:

Explanation
Knowing proper coupling and uncoupling technique is fundamental to the safe operation of combination vehicles. Improper coupling can be very dangerous.

When testing ____, you should apply your vehicle's brakes with the hand control while moving the vehicle forward slowly.

Explanation
To test the trailer service brakes, you should first ensure that the braking system has a normal air pressure level, then release the parking brake. You should then move the vehicle forward slowly and apply the brakes with the hand control. If the trailer service brakes are working properly, you will feel the brakes activate.
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