FREE DE CDL Combination Test - Practice Test 2024

1. The front trailer supports are up, and the trailer is resting on the tractor. Make sure:

there is enough clearance between the rear of the tractor frame and the landing gear.
there is enough clearance between the top of the tractor tires and the nose of the trailer.
the electrical and air connections are properly connected between the tractor and the trailer.
All of the above.

2. With brake drums, if brakes become too hot:

the brakes may stop working.
the brakes will supply too much power to the drive wheels.
your ABS will malfunction.
the air compressor will kick on to cool the brakes.

3. If your cargo only fills one-third of the length of your trailer, make sure your cargo is:

piled up high with heavy cargo on top.
centered and spread out as much as possible.
to one side and as close to the ground as possible.
loaded so there is a high center of gravity.

4. If your trailer starts to skid, you should:

pump the brakes.
steer in the opposite direction.
release the brakes.
lock the brakes.

5. If you begin to feel drowsy while driving, you should:

pull off the road and get some rest.
get some coffee.
get an energy drink.
open your window.

6. You supply air to the trailer brake system by:

connecting the tractor service air line to the trailer service glad hand.
plugging the electrical cord into the trailer.
pushing in the trailer air supply knob.
pulling out the trailer air supply valve.

7. In a vehicle with a dual air brake system:

one system supplies air to the trailer.
both systems typically operate the regular brakes on the rear axle.
each system has its own air tanks.
All of the above.

8. After starting the engine, oil pressure should rise to a normal level:

9. In vehicles with air brakes, the tractor protection valve:

keeps air in the tractor or truck brake system.
provides the air pressure used to operate trailer brakes.
is used to connect the service and emergency air lines from the truck/tractor to the trailer.
carries air, which is controlled by the trailer hand brake or the foot brake.

10. ABS helps you:

avoid wheel lock up and maintain control of your vehicle when you brake.
steer gently and smoothly while you are braking.
increase your normal braking capability.
stop much faster.

DELAWARE CDL COMBINATION PRACTICE TEST