Examkin

Soru

Zorluk: OrtaSpeed on Curves and Downgrades

Applying continuous, light pedal pressure to the service brakes throughout a long, steep downgrade descent is the recommended procedure for commercial drivers to maintain speed and prevent brake fade.

Cevap: Cevap

Cevap

False. Continuous light braking causes rapid thermal buildup and brake fade; commercial drivers must use proper gear selection combined with the snub braking technique.
Continuous application of the service brakes does not allow friction surfaces to cool. On a long descent, this constant contact generates extreme heat, causing brake fade and potential runaway vehicle conditions. The proper method relies on engine compression braking in a low gear supplemented by intermittent snub braking.

Adım Adım Çözüm

1
Analyze the mechanical effect of continuous light braking on a steep downgrade.
Continuous friction between linings and drums generates unrelenting heat with zero cooling intervals.
Brake components require release intervals to dissipate extreme thermal energy generated by holding back vehicle weight on a slope.
2
Evaluate the thermal consequence known as brake fade.
Overheated brake drums expand radially away from the brake shoes, requiring progressively more pedal travel and pressure for less stopping force.
Excessive heat glazes friction linings and reduces the coefficient of friction, potentially causing total brake failure.
3
Identify the standard CDL procedure for downgrade speed management.
Select the correct low gear before the descent and execute snub braking (applying moderate-to-firm pressure to slow 5 mph below the safe speed, then releasing).
Engine compression provides the primary retarding force, while snub braking allows cooling periods between applications.

Anahtar Kavram

Downgrade speed control and brake fade prevention
Tahmini Süre:1m 0s
Bu soruyu puanla

Konular

Speed on Curves and Downgrades

Bu konudan daha fazla soru