Free CDL study tools
Free CDL Combination Vehicles Practice Test
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What should I know before a CDL combination vehicles test?
Focus on the vehicle group, secure coupling, trailer brake connections, breakaway protection, loading and clearance for the whole combination. If you will drive a fifth-wheel tractor-trailer, check that your training and test vehicle cover that connection and any license restrictions. Practice these federal-rule scenarios, then rehearse vehicle-specific coupling and inspection with a qualified instructor.
Topics in this set
Group A requirements, fifth wheels, towbar safety, brake connections, cargo stability and whole-combination inspection.
40 questions · Practice mode
Last source review: . Source editions and limits are described below.
Practice combination vehicles
Your result
The knowledge-test pass mark is 80% under 49 CFR 383.135. This independent practice score does not predict an official result.
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10 sample questions and answers
Read these examples here, or practice the full set above. The wording is independent study material based on federal sources.
A combination has a 40,000-pound GCWR and its towed vehicle has a 15,000-pound GVWR. Which weight-based group fits?
Answer: Group A
The combination and towed-vehicle rating thresholds are both exceeded.
Report a problem with this questionDoes a towed vehicle rated above 10,000 pounds alone establish every part of Group A’s weight definition?
Answer: No, the combination-rating threshold must also be met
Evaluate both ratings and any other applicable CDL conditions.
Report a problem with this questionA Group A skills test uses a pintle connection instead of a fifth wheel. Can a tractor-trailer restriction result?
Answer: Yes
The tested connection type matters under the restriction rule.
Report a problem with this questionAn applicant fails combination knowledge but passes general knowledge. Is that enough for Group A issuance?
Answer: No
The combination portion must meet the passing requirement.
Report a problem with this questionOn the rule’s level, smooth, straight-line test, may a towed vehicle’s path deviate freely from the towing vehicle’s path?
Answer: No, the specified tolerance is three inches to either side
This is the rule’s tracking condition, not a turning-clearance measurement.
Report a problem with this questionWhen chains or cables are the safety device, what arrangement does the rule normally require on the towed vehicle?
Answer: Two separate chains or cables, or one chain or cable bridled between two widely spaced frame or axle points
Section 393.70 normally requires that chain-or-cable arrangement. A solid-tongue converter dolly has a stated exception.
Report a problem with this questionA fifth-wheel installation has warped the tractor frame. Does that satisfy the mounting requirement?
Answer: No
Installation must not crack, warp or deform the frame.
Report a problem with this questionWhat must prevent the lower fifth wheel from shifting on its mounting frame?
Answer: A positive anti-shift device
Secure mounting and positive prevention of shifting are separate requirements.
Report a problem with this questionCan the upper fifth-wheel half be attached less securely than the lower-half standard permits?
Answer: No
The upper half requires at least the same installation security.
Report a problem with this questionWhat should keep the fifth-wheel halves from separating during normal operation?
Answer: A locking mechanism that requires a positive manual release
A mechanism or adapter must prevent unintended separation.
Report a problem with this question
Sources and study scope
The bank uses original questions based on federal rules and FMCSA material. The questions use the 2025 annual CFR edition, with selected current eCFR references checked on October 28, 2026. It is not a complete review of every later amendment. Each explanation links to its federal source. State manuals are further-study links; no AAMVA manual text is reproduced.
The 80% knowledge-test pass standard comes from 49 CFR 383.135. This site’s practice pool and session lengths do not determine your state’s official test format.