Examkin

Question

Difficulty: HardSpeed on Curves and Downgrades

Applying firm service brake pressure while actively steering through a curve stabilizes a commercial vehicle by utilizing forward weight transfer to increase steering axle traction.

Answer: Answer

Answer

False
Applying service brakes while negotiating a curve forces tires to divide their available traction between turning and braking. Under firm braking, total friction demand exceeds available road grip, causing the steer wheels to lock and slide or the drive wheels to break loose into an unrecoverable jackknife. Safe operating speed must always be established prior to entering the curve.

Step-by-Step Solution

1
Analyze tire traction physics during commercial vehicle cornering.
Tire grip must be shared between lateral (turning) force and longitudinal (braking) force.
Available friction between tires and the pavement is finite according to the friction circle principle.
2
Evaluate the mechanical consequence of applying firm brakes mid-curve.
The added braking demand exceeds available tire adhesion, causing steer wheels to slide straight or drive wheels to lose lateral hold.
Weight transfer does not compensate for exceeding total friction limits and unloads rear axles.
3
Determine adherence to commercial vehicle operating standards.
Drivers must decelerate to a safe speed before entering a curve rather than braking during the maneuver.
Braking inside the turn creates dynamic instability and severe skid risks, rendering the statement false.

Key Concept

Traction limits and speed management when negotiating curves
Estimated Time:1m 30s
Rate this question

Topics

Speed on Curves and Downgrades

More questions from this topic