Combination Flashcards
The “crack-the-whip” effect can:
Turn over a trailer.
To help prevent rollovers, you should:
Drive slowly around turns.
Large combination vehicles take the longest amount of time to stop:
When empty.
What is off-tracking?
When a vehicle’s front wheels follow a different path than its rear wheels
When backing a trailer, how should you turn the steering wheel?
Turn the top of the steering wheel in the direction opposite of where you want the trailer
to go.
What does the trailer air supply control look like?
It is an eight-sided red knob.
Air pressure in the ____ air line is controlled by either the foot brake or trailer hand brake.
Service
One function of the emergency air line is to:
Control the emergency brakes.
Having ABS on only one axle:
Will allow the driver additional control over their vehicle when braking.
If a trailer begins to skid, the driver should:
Release the brakes.
The trailer hand valve should:
Be used only to test the trailer brakes.
All trailers made after ____ must be equipped with Anti-Lock Braking Systems (ABS).
1998
When a combination vehicle goes around a corner:
The front and rear wheels move in different paths.
If a parked trailer does not have spring brakes, you should keep the trailer from moving by:
Using wheel chocks.
Trailers with low underneath clearance may be difficult to drive:
Over railroad crossings.
A shut-off valve:
Prevents air from escaping an air brake system.
If a trailer is too high:
It may not couple correctly.
After coupling, there should be ____ between the upper and lower fifth wheel.
No space
When uncoupling a trailer, landing gear should be:
Firmly on the ground.
Before a drive, ensure that air flows to all trailers by:
Opening the rear shut-off valves and listening for escaping air.
Test the tractor protection valve by:
Releasing air with the brake pedal.
Pull out the trailer air supply control to test:
The trailer emergency brakes.
To prevent a rollover, a driver should:
Keep cargo low.
One way to prevent a rollover is to:
Keep cargo centered on the rig.
In a sudden turn, the ____ trailer is the most likely to turn over.
Last
Using the trailer hand brake while experiencing a trailer jackknife will:
Continue the skid.
If you need to back your trailer but cannot back up in a straight path, you should:
Back toward the driver’s side.
Using the trailer hand valve while driving:
Can cause a skid.
Push in the trailer air supply control to:
Supply the trailer with air.
In a vehicle equipped with an automatic tractor protection valve, the valve will pop out when:
Air pressure drops to a level between 20 and 45 psi.
An air supply control in its “emergency” position will:
Apply the trailer emergency brakes.
The service air line is attached to the:
Relay valves.
The emergency air line:
Supplies air to the trailer air tanks.
Trailers built before 1975 are:
Not required to have spring brakes.
While inspecting a coupling, you should go under the trailer and:
Look into the back of the fifth wheel.
If you are operating a vehicle built before 1998 and are unsure if the trailer has an Anti-Lock Braking System (ABS), you can:
Check for wheel speed sensors coming from the back of the brakes.
After finishing a pre-trip inspection, you should:
Close the emergency line valve.
After finishing a pre-trip inspection, you should:
Close the service line valve.
During a trip, which shut-off valves should be open?
All shut-off valves should be in the open position, except the rear shut-off valves.
To test the trailer service brakes, you should:
Move the vehicle forward slowly and apply the brakes with the hand control.
____ are the cause of more than half of all accident-related truck driver deaths.
Truck rollovers
When traveling more slowly than 40 mph, maintain at least ____ of following distance per
every 10 feet of your vehicle.
One second
Avoid needing to make sudden lane changes by:
Watching the road ahead while driving.
A lightly-loaded combination vehicle will stop more slowly than a fully-loaded vehicle because:
The stiff suspension springs and strong brakes will have low traction.
When driving a bobtail tractor, you should be aware that:
Bobtails are more difficult to stop than tractors with semitrailers.
Compared to other commercial motor vehicles, combination vehicles need more space on the
road because they are longer and they:
Need more space to turn and stop.
When entering or crossing traffic while driving a combination vehicle, it is especially important
that you:
Make sure there is a large enough gap for your vehicle.
An air supply control lever should be in its “normal” position when you are:
Pulling a trailer.
When glad hands are coupled, the seals should be pressed together at an angle of:
90 degrees.
In a double or triple combination:
The heaviest trailer should be positioned directly behind the cab.
