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Question

Difficulty: EasySpeed on Curves and Downgrades

When approaching and negotiating a curve in a commercial vehicle, which procedure provides the safest speed control?

  1. A
    Maintain normal cruising speed until reaching the sharpest part of the curve, then apply firm brake pressure.
  2. B
    Activate the engine retarder at maximum strength while turning so mechanical braking is avoided entirely.
  3. Reduce to a safe speed before entering the curve, then accelerate slightly through the turn.Answer
  4. D
    Delay braking until you are inside the curve to minimize the total distance traveled at reduced speed.

Answer

Reduce to a safe speed before entering the curve, then accelerate slightly through the turn.
The safest method is to reduce speed before entering the curve and then maintain slight acceleration through the turn. Braking inside a curve can lock wheels and cause a skid, whereas establishing safe speed in advance allows the vehicle to maintain stability under power.

Step-by-Step Solution

1
Assess the upcoming curve and determine a safe entry speed prior to curve entry.
Driver identifies the need to decelerate before steering into the bend.
Commercial vehicles have a high center of gravity and require speed reduction on straight road sections to prevent instability.
2
Brake smoothly and downshift to the proper gear before crossing into the curve.
The vehicle enters the turn at a controlled, safe speed in an appropriate pulling gear.
Braking while turning can easily lock the wheels and cause skidding or rollover.
3
Maintain slight, steady engine power throughout the turn.
Traction and vehicle balance are stabilized as the vehicle completes the curve.
Slight acceleration maintains positive drive-wheel traction and vehicle stability.

Key Concept

Speed management prior to entering curves to preserve tire traction and vehicle stability
Estimated Time:45s
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Topics

Speed on Curves and Downgrades

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