CDL COMBINATION VEHICLES
QUESTIONS WITH VERIFIED ANSWERS
j TRUE OR FALSE:
More than half of truck driver deaths in crashes are the result of truck rollovers. - True
Fully loaded rigs are ___ times more likely to roll over in a crash than empty rigs. - 10
What can you do to prevent rollovers? - keep the cargo close to the ground
drive slowly around turns
TRUE OR FALSE:
Keeping cargo low is even more important in combination vehicles than in straight trucks. - True
Rollovers happen when you turn too___ - Fast
Trucks with trailers have a dangerous... - crack the whip effect
TRUE OR FALSE:
When pulling trailers, a sudden movement with your steering wheel may cause your tralier to tip over. -
True
Large combination vehicles take longer to stop when they are... - Empty
How much follwoing distance should you have? - At leats 1 second for every 10 feet of vehicle length
under 40 mph.
How much following distance should you have driving 50 mph? - At least 1 second for every 10 feet of
your vehicle plus an additional second.
When lightly loaded, the very stiff suspension springs and strong brakes give poor traction. - True
TRUE OR FALSE:
Tests have shown that bobtails are easy to stop. - False
In any combination rig, allow lots of ___ distance and look far ahead. - Following
, What is the best way to recognize that the trailer has started to skid? - Seeing it in your mirriors.
TRUE OR FALSE:
When braking hard you should check your mirriors to make sure that your trailer is staying where it
should? - True
Why should you not use the trailer hand brake to straighten out a jackknifing trailer. - This is the wrong
thing to do since the brakes on the trailer wheels caused the skid in the first place.
Once the trailer wheels grip the road again, the trailer will start to follow the tractor and starighten out.
What is off tracking? - When a vehicle goes around a corner, the rear wheels of the trailer will track
further to the inside of the turn than the wheels of the tractor.
Longer vehicles will off track more.
TRUE OR FALSE:
If you must back on a curved path, back to the drivers side so you can see. - True
What type of trailers can get stuck on rail-road highway crossing? - Lowboy
Car Carrier
Why should you not use the trailer hand valve while driving? - The trailer hand valve should only be used
to test the brakes.
Do not use it in driving because of the danger of making the trailer skid.
Describe what trailer air supply control does. - You push in Red valve to supply the trailer with air, and
pull it out to shut the air off and put on the trailer emergency brakes.
The valve will pop out ( closing the tractor protection valve ) when the air pressure drops into the range
of 20-45 psi.
Describe what the service line is for. - The service line ( called the control line ) carries air, which is
controlled by the foot brake or the trailer hand brake.
QUESTIONS WITH VERIFIED ANSWERS
j TRUE OR FALSE:
More than half of truck driver deaths in crashes are the result of truck rollovers. - True
Fully loaded rigs are ___ times more likely to roll over in a crash than empty rigs. - 10
What can you do to prevent rollovers? - keep the cargo close to the ground
drive slowly around turns
TRUE OR FALSE:
Keeping cargo low is even more important in combination vehicles than in straight trucks. - True
Rollovers happen when you turn too___ - Fast
Trucks with trailers have a dangerous... - crack the whip effect
TRUE OR FALSE:
When pulling trailers, a sudden movement with your steering wheel may cause your tralier to tip over. -
True
Large combination vehicles take longer to stop when they are... - Empty
How much follwoing distance should you have? - At leats 1 second for every 10 feet of vehicle length
under 40 mph.
How much following distance should you have driving 50 mph? - At least 1 second for every 10 feet of
your vehicle plus an additional second.
When lightly loaded, the very stiff suspension springs and strong brakes give poor traction. - True
TRUE OR FALSE:
Tests have shown that bobtails are easy to stop. - False
In any combination rig, allow lots of ___ distance and look far ahead. - Following
, What is the best way to recognize that the trailer has started to skid? - Seeing it in your mirriors.
TRUE OR FALSE:
When braking hard you should check your mirriors to make sure that your trailer is staying where it
should? - True
Why should you not use the trailer hand brake to straighten out a jackknifing trailer. - This is the wrong
thing to do since the brakes on the trailer wheels caused the skid in the first place.
Once the trailer wheels grip the road again, the trailer will start to follow the tractor and starighten out.
What is off tracking? - When a vehicle goes around a corner, the rear wheels of the trailer will track
further to the inside of the turn than the wheels of the tractor.
Longer vehicles will off track more.
TRUE OR FALSE:
If you must back on a curved path, back to the drivers side so you can see. - True
What type of trailers can get stuck on rail-road highway crossing? - Lowboy
Car Carrier
Why should you not use the trailer hand valve while driving? - The trailer hand valve should only be used
to test the brakes.
Do not use it in driving because of the danger of making the trailer skid.
Describe what trailer air supply control does. - You push in Red valve to supply the trailer with air, and
pull it out to shut the air off and put on the trailer emergency brakes.
The valve will pop out ( closing the tractor protection valve ) when the air pressure drops into the range
of 20-45 psi.
Describe what the service line is for. - The service line ( called the control line ) carries air, which is
controlled by the foot brake or the trailer hand brake.
