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Difficulty: MediumCoasting and Engine Braking

During a routine journey, a driver frequently leaves the vehicle in neutral while rolling towards red traffic lights. What are TWO hazardous outcomes of this driving habit? (Select TWO answers)

  1. Engine resistance cannot assist in retarding the vehicle's momentumAnswer
  2. B
    Electronic stability and traction control systems are completely disabled
  3. The footbrake components are subjected to greater stress and risk overheatingAnswer
  4. D
    Fuel delivery to the engine is completely cut off to conserve fuel

Answer

Engine resistance cannot assist in retarding the vehicle's momentum, and the footbrake components are subjected to greater stress and risk overheating.
Coasting in neutral disengages the powertrain from the driven wheels, eliminating engine braking. Consequently, the driver must rely entirely on the footbrake, which increases mechanical wear, elevates brake temperatures, and can lead to brake fade during repeated or prolonged braking.

Step-by-Step Solution

1
Analyze the mechanical state of the powertrain during neutral coasting
The engine is decoupled from the drive wheels, removing natural powertrain drag.
Understanding power delivery and deceleration mechanics determines why control is compromised.
2
Evaluate the demands placed upon the braking system
All deceleration force must be generated solely by the disc and drum friction brakes.
Prolonged reliance on friction brakes generates excessive heat and increases stopping distances.
3
Examine common misconceptions regarding electronic assists and fuel economy
Coasting does not disengage electronic stability programs, nor does it cut fuel flow entirely.
Electronic safety systems remain powered, and idling in neutral consumes fuel to maintain engine revs.

Key Concept

Hazards of coasting and the role of engine braking in vehicle management
Estimated Time:1m 0s
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Topics

Coasting and Engine Braking

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