Examkin

Question

Difficulty: MediumMountain Driving and Steep Downgrades

If a commercial driver determines that vehicle speed is increasing while descending a steep mountain downgrade, the driver should downshift into a lower transmission gear during the descent to increase engine braking assistance.

Answer: Answer

Answer

False
According to standard commercial driving procedures, the transmission must be placed in the proper low gear before beginning the descent. Attempting to shift gears while on the grade can cause the driver to miss the shift, trapping the vehicle in neutral and resulting in a total loss of engine retarding power.

Step-by-Step Solution

1
Recall CDL regulations regarding transmission gear selection for mountain driving.
Drivers are required to select and fully engage the appropriate low gear before starting down the hill or cresting the grade.
Gravity causes the vehicle to accelerate rapidly on steep declines, preventing proper drivetrain synchronization.
2
Analyze the mechanical consequences of shifting gears while on an active downgrade.
Attempting to downshift on a downgrade often results in missing the gear, leaving the vehicle freewheeling in neutral.
Losing gear engagement eliminates all engine compression braking and forces the service brakes to absorb all gravitational kinetic energy, rapidly causing brake fade.
3
Determine the validity of the statement.
The statement recommends downshifting during downgrade descent, which is hazardous and directly contrary to CDL safety standards.
The correct answer is False.

Key Concept

Pre-Descent Gear Selection and Prohibition of Mid-Descent Shifting
Estimated Time:1m 0s
Rate this question

Topics

Mountain Driving and Steep Downgrades

More questions from this topic