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Combination Vehicles Practice Question 50

Required for Class ACombination Vehicles · Question 50

The risk of rollover is greatest when:

• AThe vehicle is empty
• BCarrying liquid or high-density loads in curves at speed
• CDriving in a straight line
• DBacking up

Correct answer: B. Carrying liquid or high-density loads in curves at speed

Why: High-density and liquid loads place high lateral forces on the trailer in curves. Reduce speed dramatically before turns and ramps.

How this question fits the Combination test

Articulated vehicles fail in unique ways: trailer swing under braking, rearward amplification under steering, and jackknife under loss of traction. Combination Vehicle knowledge is required for any Class A applicant under 49 CFR 383.111.

Study technique for this topic

Walk through the coupling sequence verbally until it's second nature. Know the safe-rolling rearward amplification factor, the difference between trailer service brakes and parking brakes, and what creates the conditions for a tractor jackknife.

Related Combination practice questions

• Q46. Inspecting the rear of a trailer at a stop should include:
• Q60. When making a tight backing maneuver, looking ahead in your mirrors to predict trailer mov…
• Q9. The coupling height check before backing under the trailer is critical because:
• Q22. Air lines and electrical cables between tractor and trailer must be:
• Q35. Antilock brakes on a tractor without ABS on the trailer:

Continue your CDL preparation

The Combination Vehicles portion of the CDL knowledge exam covers more than this single question. Use this site's full Combination Vehicles bank to drill every topic, then test yourself with one of our state-specific practice sets to confirm you are ready for the actual DMV exam in your state. Always check your state's CDL handbook for any local addenda before the test day.

If you are still building your overall CDL foundation, start with the General Knowledge bank — every CDL applicant must pass it — and then work outward to the endorsements you plan to add.