25 realistic Doubles and Triples practice questions for Ohio CDL applicants. Required for: Drivers pulling more than one trailer. Official test: 20 questions, 16 correct to pass.
Question 1 of 25 · Vehicle Dynamics
Doubles and triples have ____ rollover risk than single trailers.
-
A.
Lower
-
B.
Higher
-
C.
The same
-
D.
No rollover risk
Correct answer: B.
Multiple trailers have higher rollover risk because of greater articulation and "crack-the-whip" effect.
Question 2 of 25 · Skids
What should you do if a trailer starts to skid?
-
A.
Release the brakes to allow trailer wheels to roll
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B.
Apply more brake
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C.
Steer hard right
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D.
Accelerate
Correct answer: A.
Release brakes to let trailer wheels roll; steer to recover.
Question 3 of 25 · Emergency Maneuvers
How should doubles drivers handle emergency braking?
-
A.
Apply brakes firmly but smoothly
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B.
Use only the trailer hand valve
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C.
Pump the brakes
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D.
Use only the engine retarder
Correct answer: A.
Smooth, firm braking is best — let ABS work if equipped.
Question 4 of 25 · Inspection
Why is it important to inspect each trailer separately?
-
A.
Each trailer has its own systems and potential issues
-
B.
It's easier to spot problems
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C.
It's required by law
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D.
All of the above
Correct answer: D.
Each trailer needs its own inspection of brakes, lights, and condition.
Question 5 of 25 · Coupling
What's a common mistake when coupling doubles?
-
A.
Not properly aligning the dolly with the second trailer
-
B.
Forgetting to connect air lines
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C.
Not testing the brakes
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D.
All of the above
Correct answer: D.
Alignment, air lines, and brake tests are common areas for mistakes.
Question 6 of 25 · Cargo
What's the impact of overloading a trailer in a doubles set?
-
A.
Increased rollover risk
-
B.
Poor handling
-
C.
Brake problems
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D.
All of the above
Correct answer: D.
Overloading creates a chain of safety problems for the whole combination.
Question 7 of 25 · Inspection
When inspecting doubles and triples, what should you check?
-
A.
Each trailer's lights and brakes
-
B.
Each converter dolly
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C.
Each fifth wheel and pintle hook
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D.
All of the above
Correct answer: D.
Inspect every trailer, dolly, fifth wheel, and pintle hook before driving.
Question 8 of 25 · Coupling
What's a "spider" or "dolly converter"?
-
A.
A type of trailer
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B.
A coupling device with a fifth wheel mounted on a single axle
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C.
A type of brake
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D.
A safety chain
Correct answer: B.
Converter dollies have a fifth wheel and an axle to allow connecting trailers.
Question 9 of 25 · Coupling
What is the pintle hook?
-
A.
A coupling device on the dolly that connects to the lead trailer's pintle plate
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B.
A type of tire
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C.
A safety chain
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D.
A brake component
Correct answer: A.
The pintle hook on the dolly connects to the lead trailer for towing.
Question 10 of 25 · Following Distance
What's the safe way to handle a doubles in heavy traffic?
-
A.
Maintain extra following distance and signal early
-
B.
Speed up to keep with traffic
-
C.
Use the shoulder
-
D.
Drive aggressively
Correct answer: A.
Extra space and early signals are critical in heavy traffic with combinations.
Question 11 of 25 · Backing
When backing doubles or triples, you should:
-
A.
Avoid backing if possible
-
B.
Use a helper as a spotter
-
C.
Back slowly and carefully
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D.
All of the above
Correct answer: D.
Avoid backing combinations; use a spotter and go slowly when you must.
Question 12 of 25 · Inspection
What's the impact of poor maintenance on doubles or triples?
-
A.
Increased risk of breakdowns and accidents
-
B.
Poor fuel efficiency
-
C.
Legal issues
-
D.
All of the above
Correct answer: D.
Poor maintenance leads to safety, efficiency, and legal problems.
Question 13 of 25 · Vehicle Dynamics
When making a turn, the front trailer of a doubles set:
-
A.
Tracks like a single trailer
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B.
Off-tracks more than the tractor
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C.
Stays in line with the tractor
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D.
Off-tracks less than the rear trailer
Correct answer: D.
The rear trailer off-tracks more than the front, so the rear is more likely to hit obstacles.
Question 14 of 25 · Vehicle Dynamics
What is "crack-the-whip"?
-
A.
A driver discipline rule
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B.
When the rear trailer swings out due to sudden steering inputs
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C.
A type of weight distribution
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D.
A coupling procedure
Correct answer: B.
The rear trailer can swing far wider than the tractor, magnifying steering inputs.
Question 15 of 25 · Coupling
Where should the heaviest trailer go in a doubles or triples set?
-
A.
First (closest to the tractor)
-
B.
Last (farthest from the tractor)
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C.
Anywhere
-
D.
In the middle
Correct answer: A.
Place the heaviest trailer behind the tractor for best stability.
Question 16 of 25 · Coupling
What's the proper procedure for coupling a second trailer?
-
A.
Position the dolly under the second trailer, then back the lead trailer to the dolly
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B.
Drive the lead trailer over the dolly
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C.
Connect electrical first
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D.
Lower the landing gear
Correct answer: A.
Position the dolly first, then back the lead trailer to it for proper coupling.
Question 17 of 25 · Combination Air
What's the role of glad hands in doubles and triples?
-
A.
They connect air lines between each unit
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B.
They are coupling devices
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C.
They are safety chains
-
D.
They are landing gear
Correct answer: A.
Glad hands connect service and emergency air lines between every unit.
Question 18 of 25 · Mountain Driving
What's the recommended speed when descending a steep grade with doubles?
-
A.
Slow speed using lower gears and engine braking
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B.
Posted speed limit
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C.
Faster than single trailers
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D.
Use service brakes only
Correct answer: A.
Use lower gears and engine braking. Service brakes only intermittently.
Question 19 of 25 · Speed Management
What's the safe speed for taking corners with doubles or triples?
-
A.
Posted speed limit
-
B.
Slower than single trailers
-
C.
Higher than single trailers
-
D.
No different from single trailers
Correct answer: B.
Take corners more slowly than single trailers due to greater rollover risk.
Question 20 of 25 · Lane Changes
What's the major risk when changing lanes with doubles or triples?
-
A.
The rear trailer may not follow exactly
-
B.
Other vehicles may not see the long combination
-
C.
The trailer may swing out
-
D.
All of the above
Correct answer: D.
Visibility and rear-trailer tracking are both major lane-change risks.
Question 21 of 25 · Cargo
Doubles and triples are most stable when:
-
A.
All trailers are properly loaded
-
B.
Trailers are empty
-
C.
The lead trailer is empty
-
D.
The rear trailer is heaviest
Correct answer: A.
Proper loading on every trailer is key to stability.
Question 22 of 25 · Coupling
What's the role of safety chains on a converter dolly?
-
A.
To support the dolly when uncoupled
-
B.
To prevent the trailer from coming loose if the pintle hook fails
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C.
To improve traction
-
D.
To act as a brake
Correct answer: B.
Safety chains keep the trailer attached if the pintle hook fails.
Question 23 of 25 · CDL Rules
Triples are illegal in many states because:
-
A.
They are too long and cause traffic disruption
-
B.
They have higher rollover risk
-
C.
They require special permits
-
D.
All of the above
Correct answer: D.
Many states prohibit triples due to length, rollover risk, and special permitting needs.
Question 24 of 25 · Operation
How should drivers approach intersections with doubles or triples?
-
A.
Slow down and signal early to allow for the turn
-
B.
Drive at full speed
-
C.
Cut across lanes if needed
-
D.
Use the engine retarder
Correct answer: A.
Slow down and signal well in advance to give time for the long combination.
Question 25 of 25 · Operation
What's the safest way to merge into traffic with doubles?
-
A.
Use turn signals early and merge gradually
-
B.
Speed up to merge quickly
-
C.
Force other drivers to yield
-
D.
Drive on the shoulder
Correct answer: A.
Signal early and merge gradually so other drivers can adjust.
About the Doubles and Triples Test
The Doubles and Triples test covers pulling double and triple trailers, coupling and uncoupling, inspecting doubles and triples, antilock brake systems, and safe driving with multiple trailers. Doubles and triples are more likely to roll over than single trailers and are extremely sensitive to steering inputs at the rear trailer.
The Ohio Bureau of Motor Vehicles administers this knowledge test as part of its commercial driver license program. To earn the Doubles/Triples (T) on your Ohio CDL, you need to score at least 16 out of 20 on the official version.
Topics covered on this practice test
- Coupling: 6 questions
- Vehicle Dynamics: 3 questions
- Inspection: 3 questions
- Cargo: 2 questions
- Operation: 2 questions
- Skids: 1 question
- Emergency Maneuvers: 1 question
- Following Distance: 1 question
- Backing: 1 question
- Combination Air: 1 question
- Mountain Driving: 1 question
- Speed Management: 1 question
- Lane Changes: 1 question
- CDL Rules: 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 Ohio until you're ready for the official exam.
Tips specific to the Doubles and Triples test
Doubles and Triples questions emphasize the "crack-the-whip" effect, converter dolly inspection and use, pintle hooks, safety chains, the heaviest-trailer-first loading rule, and the higher rollover risk of multi-trailer combinations. Many states prohibit triples; check local rules.