25 realistic Combination Vehicles practice questions for Montana CDL applicants. Required for: Class A CDL (tractor-trailer combinations). Official test: 20 questions, 16 correct to pass.
Question 1 of 25 · Operation
Which of these is most important when driving with a trailer?
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A.
Use the engine retarder constantly
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B.
Use proper braking and signaling
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C.
Drive at maximum speed limits
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D.
Skip pre-trip checks if running late
Correct answer: B.
Proper braking and clear signaling are essential to safe combination driving.
Question 2 of 25 · Backing
Which is correct about backing a tractor-trailer?
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A.
Steer in the same direction you want the trailer to go
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B.
Steer in the opposite direction you want the trailer to go
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C.
Use the throttle to back
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D.
Back as fast as possible
Correct answer: B.
When backing, turn the steering wheel opposite to the direction you want the trailer to move.
Question 3 of 25 · Inspection
What is the proper way to test the parking brakes after coupling?
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A.
Apply trailer parking brake and try to gently pull forward
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B.
Drive at normal speed
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C.
Apply foot brake repeatedly
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D.
Disconnect glad hands
Correct answer: A.
A gentle pull forward with parking brakes set confirms holding power.
Question 4 of 25 · Vehicle Dynamics
Why should you avoid sudden steering and braking with combinations?
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A.
It wears tires faster
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B.
It can cause jackknife or rollover
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C.
It uses more fuel
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D.
It scares passengers
Correct answer: B.
Sudden inputs can break traction and lead to jackknifing or rollovers.
Question 5 of 25 · CDL Rules
Which is true about long combination vehicles (LCVs)?
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A.
They are easier to maneuver in tight spaces
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B.
They require additional driver training and special permits
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C.
They handle the same as single trailers
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D.
They never require special routes
Correct answer: B.
LCVs need extra training, certifications, and often follow restricted routes.
Question 6 of 25 · Following Distance
What is "rear-end collision" risk for combination vehicles?
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A.
It is reduced when carrying long cargo
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B.
They have a higher risk because of long stopping distances and rear blind spots
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C.
They have no greater risk
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D.
Only for empty rigs
Correct answer: B.
Long stopping distance and rear blind spots increase rear-end collision risk.
Question 7 of 25 · Coupling
When you finish coupling, the air lines should be:
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A.
Connected to the proper glad hands and supported off the catwalk and the deck plate
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B.
Coiled tightly on top of the trailer
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C.
Loose so they can move freely
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D.
Disconnected
Correct answer: A.
Air lines must be connected and supported off the deck so they don't snag or wear.
Question 8 of 25 · Combination Air
What is glad hands?
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A.
Trailer doors
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B.
Couplers used to join air lines from the tractor to the trailer
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C.
Mirror brackets
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D.
Brake levers
Correct answer: B.
Glad hands connect the service and emergency air lines between tractor and trailer.
Question 9 of 25 · Vehicle Dynamics
Off-tracking is most pronounced in:
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A.
Single vehicles
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B.
Long combinations and curves
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C.
Empty trailers
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D.
Vehicles with disc brakes
Correct answer: B.
Longer wheelbases and tighter curves cause greater off-tracking.
Question 10 of 25 · Inspection
Which of these is not a part of the trailer's electrical system?
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A.
Lights
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B.
Brake control
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C.
Power line cord (pigtail)
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D.
Hydraulic pump
Correct answer: D.
Hydraulic pumps are not part of standard trailer electrical systems on highway combinations.
Question 11 of 25 · Skids
What should you do to recover from a trailer skid?
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A.
Apply more brake pressure
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B.
Release the brakes to allow trailer wheels to roll again
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C.
Steer hard right
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D.
Accelerate forward
Correct answer: B.
Release brakes to let trailer wheels roll, then steer to recover direction.
Question 12 of 25 · Vehicle Dynamics
When you turn suddenly with a high center of gravity, the trailer can:
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A.
Roll over
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B.
Stop more quickly
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C.
Track better
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D.
Reduce fuel use
Correct answer: A.
High centers of gravity make trailers prone to rollover during sharp turns.
Question 13 of 25 · Vehicle Dynamics
Which of these is true about the front trailer of a doubles or triples?
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A.
It is less likely to overturn
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B.
It is more stable
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C.
It is more likely to overturn than the rear trailer
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D.
It does not need brakes
Correct answer: A.
The front trailer in a combination is generally more stable than the rear trailer.
Question 14 of 25 · Skids
How can drivers avoid jackknifing?
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A.
Brake gently and look ahead
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B.
Adjust speed for road and weather
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C.
Use ABS where equipped
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D.
All of the above
Correct answer: D.
Smooth braking, appropriate speed, and ABS all reduce jackknife risk.
Question 15 of 25 · Combination Air
What should the tractor protection valve do?
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A.
Keep tractor air supply if trailer breaks away or develops a major leak
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B.
Set the trailer parking brake on a hill
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C.
Apply trailer brakes during a normal stop
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D.
Disconnect the trailer
Correct answer: A.
It protects the tractor air supply by closing if a major air loss occurs.
Question 16 of 25 · Vehicle Dynamics
What is "off-tracking"?
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A.
When the rear wheels follow a different path than the front wheels
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B.
When the trailer slides off the road
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C.
When the trailer is improperly loaded
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D.
A type of fifth wheel
Correct answer: A.
In turns, rear wheels travel a smaller arc than the front, causing off-tracking.
Question 17 of 25 · Emergency Equipment
What are some common causes of vehicle fires?
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A.
Under-inflated tires and electrical short circuits
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B.
Improper use of flares
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C.
Cargo that catches fire from spilled fuel
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D.
All of the above
Correct answer: D.
All of these can cause vehicle fires. Pre-trip and en-route inspections reduce risk.
Question 18 of 25 · Combination Air
Trailer brakes are required to be:
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A.
Adjusted properly and matched to tractor brakes
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B.
Stronger than tractor brakes
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C.
Disengaged on level roads
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D.
Off when empty
Correct answer: A.
Trailer brakes must be in proper adjustment and balance with tractor brakes.
Question 19 of 25 · Coupling
What is the fifth wheel?
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A.
A spare wheel
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B.
A coupling device that connects the tractor to the trailer
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C.
A device on the trailer to support cargo
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D.
A type of axle
Correct answer: B.
The fifth wheel is the round, plate-shaped coupling that connects the tractor to the trailer.
Question 20 of 25 · Bobtail
What happens if you bobtail (no trailer) and brake hard?
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A.
You stop more quickly than loaded
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B.
Drive wheels can lock and skid because there is little weight on them
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C.
Vehicle handles like a loaded truck
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D.
No special concerns
Correct answer: B.
Bobtailing leaves little weight on drive axles, increasing skid risk under hard braking.
Question 21 of 25 · Cargo
What can cause a high center of gravity?
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A.
Loading cargo too low
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B.
Loading cargo too high or unevenly
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C.
Driving too slowly
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D.
Empty trailers
Correct answer: B.
Stacking cargo too high or loading unevenly raises the center of gravity and rollover risk.
Question 22 of 25 · Coupling
Which is true about pulling away after coupling?
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A.
Test that the kingpin is locked by gently pulling forward against the trailer brakes
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B.
Pull away as quickly as possible
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C.
Lower the landing gear before pulling away
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D.
Disconnect the air lines first
Correct answer: A.
A pull-test confirms the kingpin is locked before driving away.
Question 23 of 25 · Coupling
What is the proper position for the fifth wheel?
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A.
Tilted down toward the rear of the tractor with jaws open
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B.
Pointed straight up
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C.
Locked and ready
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D.
Removed for inspection
Correct answer: A.
Before coupling, the fifth wheel should tilt down toward the rear with the jaws open.
Question 24 of 25 · Combination Air
Trailer hand valve is used to:
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A.
Test trailer brakes
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B.
Park the trailer
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C.
Bypass the foot valve
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D.
Drain trailer tanks
Correct answer: A.
Use the trailer hand valve only for testing — not for parking or normal stops.
Question 25 of 25 · Skids
What can cause a trailer skid in a combination vehicle?
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A.
Locked trailer wheels and over-application of brakes
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B.
Light loads on the trailer
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C.
Tight steering at low speed
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D.
High pressure in steering tires
Correct answer: A.
Locked trailer wheels cause trailer skid; reduce brake pressure to recover.
About the Combination Vehicles Test
The Combination Vehicles test covers driving combination vehicles safely, combination vehicle air brakes, antilock brake systems, coupling and uncoupling, and inspecting a combination vehicle. Combination vehicles are usually heavier, longer, and require more driving skill than single commercial vehicles. They are also more likely to roll over and jackknife.
The Montana Motor Vehicle Division administers this knowledge test as part of its commercial driver license program. To earn the Combination Vehicles on your Montana CDL, you need to score at least 16 out of 20 on the official version.
Topics covered on this practice test
- Vehicle Dynamics: 5 questions
- Coupling: 4 questions
- Combination Air: 4 questions
- Skids: 3 questions
- Inspection: 2 questions
- Operation: 1 question
- Backing: 1 question
- CDL Rules: 1 question
- Following Distance: 1 question
- Emergency Equipment: 1 question
- Bobtail: 1 question
- Cargo: 1 question
How to use this practice test
- Read each question carefully. CDL questions are written precisely — small wording differences matter.
- Click "Show Answers & Explanations" only after answering every question. Don't peek mid-test.
- Read the explanation for every question, even ones you got right. The reasoning is more important than the answer.
- Repeat the test until you score 100%. The questions are deterministic per state, so you can track your improvement over multiple sessions.
- Move on to the other endorsement tests for Montana until you're ready for the official exam.
Tips specific to the Combination Vehicles test
Combination Vehicles questions cover off-tracking, jackknifing, coupling and uncoupling, the fifth wheel, kingpin, glad hands, landing gear, and the special air-brake considerations for tractor-trailer combinations. Expect detailed step-by-step coupling questions.