This is the final step to your Class A license. The CDL Combination Practice Test covers tractor-trailers, coupling procedures, and rollover prevention.
The "Combination" endorsement allows you to drive vehicles with a GCWR of 26,001+ lbs where the trailer is heavier than 10,000 lbs.
Operate semis and combination vehicles for freight companies and long-haul carriers.
Unlock the big rigs and long-haul pay. Class A drivers earn significantly more.
Access to a wider range of trucking jobs and career advancement paths.
Passing Score
Questions
License Class
Failing to couple correctly is dangerous. If you drop a trailer on the road, your career is over.
Ensure it is greased and tilted down towards the rear.
Connect Service (Blue) and Emergency (Red) lines before backing under.
Back under slowly until the fifth wheel locks. Check the connection by pulling forward gently (Tug Test).
Get out and verify there is no space between the upper and lower fifth wheel.
Raise the landing gear fully only after the coupling is secure.
Understanding the difference between service and emergency lines is critical.
Also called the "Control Line"
Also called the "Supply Line"
Myth: Fully loaded rigs are 10x more likely to roll over in a crash than empty ones?
Fact: False. Empty trailers roll over more easily because they are lighter and bounce more. The rear trailer amplifies any swerve ("Crack-the-Whip").
The rear wheels follow a different path than the front wheels. When turning right, use the Buttonhook method (go wide into the intersection).
"I kept confusing the Jug Handle and Buttonhook turns. The explanation on this page cleared it up instantly. Passed in NY!"
"The coupling checklist is gold. I memorized it right before my test and got 100% on that section."
Everything you need to know about the Combination Vehicles test
It is considered moderately difficult. The hardest part is remembering the correct order for coupling and uncoupling, and understanding air brake connections.
Most states have 20 questions. You typically need to answer 16 correctly (80%) to pass and get your Class A permit.
If you cross the air lines (red to blue, blue to red), you will not have trailer brakes. The trailer spring brakes may not release, or they may not work when you press the pedal.
It is a driving technique for sharp right turns. You drive deep into the intersection before turning, rather than swinging left into the other lane (Jug Handle).
The trailer hand valve (trolley valve) should only be used for testing brakes. Using it while driving can cause the trailer wheels to lock up and skid, leading to a jackknife.
Master the coupling procedures and turn techniques with our CDL Combination Practice Test.
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