While operating a tractor-trailer on a rural highway, a driver approaches a continuous downhill grade that leads into several sharp bends. What is the proper speed management procedure the driver must execute to safely navigate this section of roadway?
- AMaintain cruising gear and apply continuous, light pedal pressure on the service brakes throughout the entire downgrade to stabilize speed before entering the bends.
- Shift into an appropriate low gear before starting down the grade, rely on engine braking, and reduce speed to a safe level prior to entering each curve.Answer
- CEnter the downhill curves at normal highway cruising speed and apply firm service braking while actively steering through each curve to bleed off momentum.
- DRely primarily on auxiliary retarders while actively negotiating wet downhill curves, leaving the service brakes untouched until exiting.
Answer
Shift into an appropriate low gear before starting down the grade, rely on engine braking, and reduce speed to a safe level prior to entering each curve.
Safe commercial vehicle operation requires matching speed to the terrain before encountering hazards. Shifting to an appropriate low gear before beginning a descent allows engine braking to serve as the primary speed-limiting mechanism, protecting service brakes from thermal overload. Furthermore, drivers must complete all necessary deceleration on straight roadway prior to entering a curve to avoid exceeding tire lateral adhesion limits.
Step-by-Step Solution
Key Concept
Downgrade speed control and pre-curve deceleration
Estimated Time:1m 15s