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Question

Difficulty: EasySpeed on Curves and Downgrades

A commercial vehicle operator is approaching a sharp curve on a rural highway. What is the correct chronological sequence of driver actions required to safely negotiate this curve from initial approach to completion?

  1. 1Apply service brakes on the straight roadway before entering the curve to reduce vehicle speed to a safe level.
  2. 2Downshift into an appropriate lower gear before beginning the turn to maintain engine control.
  3. 3Steer through the curve while applying light, steady throttle pressure without braking.
  4. 4Accelerate gradually back to highway speed after the vehicle has fully straightened out upon exiting the curve.

Answer

The correct chronological sequence begins with braking on the straight approach to a safe speed, downshifting into a lower gear before the turn, steering through the curve with light and steady throttle, and finally accelerating gently once the vehicle has fully straightened out after exiting.
Safe vehicle operation mandates completing all braking and gear selection on the straight roadway before turning the steering wheel. Once inside the curve, the driver maintains steady, light power to keep traction stable, and only accelerates once the vehicle has straightened out on the exit roadway.

Step-by-Step Solution

1
Decelerate on the straight road prior to the curve entry point.
Vehicle speed is reduced safely before lateral cornering forces act on the vehicle.
Braking in a straight line minimizes the risk of wheels locking up or inducing a rollover.
2
Select a suitable lower gear before turning.
The drivetrain is properly engaged without needing clutch or shift operations mid-turn.
Shifting mid-curve can interrupt power delivery, upset vehicle balance, and reduce control.
3
Guide the vehicle through the turn with light, steady throttle application.
Traction is maintained across all drive axles throughout the curve.
Gentle throttle prevents deceleration forces that could cause trailer push or jackknifing while off the brakes.
4
Apply gradual acceleration as the vehicle leaves the curve.
The vehicle smoothly transitions back to cruising speed.
Accelerating out of the curve straightens the combination vehicle and restores normal travel speed safely.

Key Concept

Safe curve negotiation requires speed reduction and gear selection before curve entry, steady power through the turn, and acceleration only after exiting.
Estimated Time:45s
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Topics

Speed on Curves and Downgrades

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