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Difficulty: MediumBalance and Center of Gravity

Commercial vehicles carrying freight with a high center of gravity can safely negotiate highway curves and exit ramps at the posted advisory speed without risk of tipping over.

Answer: Answer

Answer

False
The statement is false. An elevated center of gravity substantially reduces a commercial vehicle's roll stability in curves and evasive maneuvers. Because highway curve advisory speeds are engineered for standard passenger automobiles, top-heavy commercial vehicles can roll over even when operating at or below the posted advisory speed.

Step-by-Step Solution

1
Analyze the physical relationship between cargo placement height and vehicle rollover risk.
Freight stacked high shifts the vehicle's overall center of gravity upward, which amplifies tipping moments and lowers the roll stability threshold during cornering.
A high center of gravity makes commercial vehicles far more vulnerable to centrifugal forces encountered in turns.
2
Evaluate the calibration standard of posted highway curve advisory speeds.
Advisory speed signs on ramps and curves are engineered for passenger cars with low centers of gravity, not heavy commercial vehicles.
Understanding speed calibration prevents drivers from falsely assuming advisory speeds guarantee safety for all vehicle configurations.
3
Determine the validity of the presented statement.
The statement is false because top-heavy commercial vehicles can roll over even when traveling strictly at or below posted curve advisory speeds.
Safe CDL operation requires reducing speed well below the posted advisory speed when transporting top-heavy freight.

Key Concept

Impact of High Center of Gravity on Cornering Rollover Risk
Estimated Time:1m 0s
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Topics

Balance and Center of Gravity

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