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Question

Difficulty: MediumBalance and Center of Gravity

Posted highway ramp advisory speed limits are safe benchmarks for commercial motor vehicles transporting high center-of-gravity freight because these posted limits are calibrated for the stability limits of loaded tractor-trailers.

Answer: Answer

Answer

False
The correct answer is False because posted ramp and curve advisory speeds are engineered for standard passenger automobiles with low centers of gravity. Commercial motor vehicles hauling high center-of-gravity freight experience much higher rollover tendencies and must negotiate curves and ramps well below posted advisory speeds.

Step-by-Step Solution

1
Analyze the vehicle dynamics associated with a high cargo center of gravity.
A high center of gravity elevates the vehicle's roll center and drastically reduces its lateral stability during cornering.
Top-heavy loads amplify lateral centrifugal forces acting on the trailer, increasing rollover risk.
2
Evaluate how posted highway curve and ramp advisory speed limits are determined.
Highway advisory speed limits are calculated based on the handling capabilities and low center of gravity of standard passenger cars.
Advisory signs do not account for the elevated mass and reduced rollover threshold of commercial freight vehicles.
3
Determine the proper operating speed for commercial vehicles under these conditions.
Commercial drivers carrying high center-of-gravity loads must travel significantly below the posted advisory ramp speed to prevent tipping.
Following the posted passenger-car benchmark can lead to a catastrophic rollover crash.

Key Concept

Impact of High Center of Gravity on Cornering Stability and Advisory Speeds
Estimated Time:1m 0s
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Topics

Balance and Center of Gravity

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