FREE Michigan CDL Combination Test 2024 (Practice Test)

1. If your vehicle is equipped with air brakes, loss of air pressure in the emergency line causes:

the trailer spring brakes to come on.
the trailer emergency brakes to come on.
the speed of your vehicle to increase.

2. If your truck catches fire, the first thing you should do is to:

pull into a service station and call for help.
pull off the road and park in an open area.
get the vehicle off the road and park near other vehicles.

3. Hydroplaning:

only happens when tire pressure is higher than normal.
only occurs at extremely high speeds.
can occur at speeds as low as 30 mph.

4. As you approach off ramps and on ramps, remember:

that the posted speed limit may not be safe for larger vehicles.
that downgrades make it easier to reduce speed.
to always brake and turn at the same time.

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

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

6. The emergency air line:

supplies air to the trailer air tanks.
controls the emergency brakes on combination vehicles.
All of the above.

7. When checking the lights before driving:

you should check them from inside the vehicle.
make sure the parking brake is not set.
you should turn off the engine.

8. If you unlock the pintle hook with the dolly still under the rear trailer:

the dolly tow bar may fly up.
your vehicle might roll away.
the brakes could be damaged by the combined forces of the springs and the air pressure.

9. Combination vehicles have __ air lines.

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

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