FREE DE CDL Combination Test (2021)

1. Transporting hanging meat requires special attention. Why?

Because you have to drive fast to get it delivered fresh.
Because refrigerated trucks have less traction.
Because hanging meat can be an unstable load with a high center of gravity.
All of the above.

2. When parking a trailer without spring brakes, it is very important for safety that you use wheel chocks. Why?

The air could leak out of the trailer air tank, releasing its emergency brakes.
if you don't use wheel chocks, supply air will be sent to the service line instead of going to charge the trailer air tanks.
You may not notice a major leak in the service line until you try to put the brakes on.
None of the above.

3. A high center of gravity means:

a rollover is less likely.
you'll have better traction.
you are more likely to tip over.
the spring brakes will come fully on.

4. When backing a trailer, you should:

try to position your vehicle so you can back on a curved path.
avoid using the brakes.
turn the steering wheel in the opposite direction of the turn.
turn the steering wheel toward the direction you want to go.

5. The best way to test the trailer service brakes is to:

accelerate to the maximum possible speed, then apply the trailer brakes fully.
pull forward quickly, then apply the trailer brakes with your hand control.
put the handbrake on when there are no vehicles around you.
None of the above.

6. Most truck driver deaths in crashes result from:

following too closely.
truck rollovers.
driving side-by-side with another truck.
off-tracking.

7. If you have a manual transmission, when stopping don't _______ until the engine rpm is down close to idle.

shift to second gear
place the transmission in park
push the clutch in
apply the brakes

8. The iron trailer supports are up, and the full weight of the trailer is resting on the tractor. Make sure:

the safety latch is not engaged.
there is enough clearance between the upper and lower fifth wheel.
you are in a low enough gear.
there is enough clearance between the rear of the tractor frame and the landing gear.

9. In combination vehicles with air brakes, the trailer air supply control:

is used to control the tractor protection valve.
is used to keep the trailer behind the tractor.
is a coupling devices used to connect the service and emergency air-lines from the tractor to the trailer.
supplies air to the trailer air tanks.

10. Headache racks:

protect you from being hit by your cargo.
can blind other drivers.
help you keep weights within legal limits.
None of the above.

DE CDL COMBINATION PRACTICE TEST