MVA CDL Combination Vehicles Study
Guide Exam Questions and Answers
What two things are important to prevent rollover? -
correct answer ✅Keep cargo as close to the ground as possible;
Drive slowly around turns.
When you turn suddenly while pulling doubles, which trailer is most
likely to turn over? -
correct answer ✅The rear trailer is twice as likely to turn over.
Why should you not use the trailer hand brake to straighten out a
jackknifing trailer? -
correct answer ✅Because the brakes on the trailer wheels caused
the skid in the first place.
What is off-tracking? -
correct answer ✅When a vehicle goes around a corner and the
rear wheels follow a different path than the front wheels.
When you back a trailer, you should position your vehicle so you
can back in a curved path ____________________. -
correct answer ✅To the drivers side so you can see
, MVA CDL Combination Vehicles Study
Guide Exam Questions and Answers
What type of trailers can get stuck on railroad-highway crossings? -
correct answer ✅Low slung units (lowboy, car carrier, moving van,
possum-belly livestock trailer); Single-axle tractor pulling a long
trailer with its landing gear set to accommodate a tandem-axle
tractor.
Why should you not use the trailer hand valve while driving? -
correct answer ✅Because of the danger of making the trailer skid.
Describe what the trailer air supply control does. -
correct answer ✅You push it in to supply the trailer brakes with air,
and pull it out to shut off the air supply to put the trailer emergency
brakes on.
Describe what the service line is for. -
correct answer ✅(Also called the control line or signal line) Carries
air, which is controlled by the foot brake or trailer hand brake.
Depending on how hard you press the foot brake or hand valve, the
pressure in the service line will similarly change.
What is the emergency air-line for? -
correct answer ✅It supplies air to the trailer air tanks; controls the
emergency brakes on combination vehicles.
Guide Exam Questions and Answers
What two things are important to prevent rollover? -
correct answer ✅Keep cargo as close to the ground as possible;
Drive slowly around turns.
When you turn suddenly while pulling doubles, which trailer is most
likely to turn over? -
correct answer ✅The rear trailer is twice as likely to turn over.
Why should you not use the trailer hand brake to straighten out a
jackknifing trailer? -
correct answer ✅Because the brakes on the trailer wheels caused
the skid in the first place.
What is off-tracking? -
correct answer ✅When a vehicle goes around a corner and the
rear wheels follow a different path than the front wheels.
When you back a trailer, you should position your vehicle so you
can back in a curved path ____________________. -
correct answer ✅To the drivers side so you can see
, MVA CDL Combination Vehicles Study
Guide Exam Questions and Answers
What type of trailers can get stuck on railroad-highway crossings? -
correct answer ✅Low slung units (lowboy, car carrier, moving van,
possum-belly livestock trailer); Single-axle tractor pulling a long
trailer with its landing gear set to accommodate a tandem-axle
tractor.
Why should you not use the trailer hand valve while driving? -
correct answer ✅Because of the danger of making the trailer skid.
Describe what the trailer air supply control does. -
correct answer ✅You push it in to supply the trailer brakes with air,
and pull it out to shut off the air supply to put the trailer emergency
brakes on.
Describe what the service line is for. -
correct answer ✅(Also called the control line or signal line) Carries
air, which is controlled by the foot brake or trailer hand brake.
Depending on how hard you press the foot brake or hand valve, the
pressure in the service line will similarly change.
What is the emergency air-line for? -
correct answer ✅It supplies air to the trailer air tanks; controls the
emergency brakes on combination vehicles.
