While driving down a long, steep mountain incline, a driver continuously applies the foot brake to control speed rather than shifting into a lower gear. After several miles, the brake pedal feels increasingly soft and spongy, and the vehicle requires much greater distance to slow down. What is the primary cause of this dangerous condition?
- Brake fade caused by extreme heat buildup from continuous friction, which overheating reduces braking friction and boils brake fluidAnswer
- BViolation of the basic speed law caused by exceeding posted downhill speed limits on mountain curves
- CMisinterpreting diamond warning signs that require drivers to bring the vehicle to a complete stop before steep grades
- DTire traction loss resulting from hydroplaning on dry mountain pavement during high-friction downhill braking
Answer
The primary cause of the soft pedal and reduced stopping power is brake fade resulting from extreme thermal buildup when foot brakes are applied continuously on steep downhill grades.
Continuous pressure on the foot brake while descending a steep grade creates severe thermal accumulation. This heat degrades pad friction and can boil brake fluid, causing brake fade and a spongy pedal. Downshifting to use engine braking prevents this hazard.
Step-by-Step Solution
Key Concept
Brake fade and thermal management during steep mountain descents
Estimated Time:1m 0s