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Zorluk: ZorStopping Distances

You are driving a car at 40 mph40\text{ mph} along a single carriageway during persistent rain. According to The Highway Code, what is the typical minimum overall stopping distance required under these conditions?

  1. A
    36 metres (120 feet)
  2. B
    48 metres (160 feet)
  3. 72 metres (240 feet)Cevap
  4. D
    60 metres (200 feet)

Cevap

72 metres (240 feet)
Under dry conditions at 40 mph40\text{ mph}, a car has a thinking distance of 12 metres12\text{ metres} (40 feet40\text{ feet}) and a braking distance of 24 metres24\text{ metres} (80 feet80\text{ feet}), totaling 36 metres36\text{ metres} (120 feet120\text{ feet}). Because wet road surfaces reduce tyre friction and significantly impair braking efficiency, The Highway Code states that overall stopping distances in wet conditions are at least double those in dry conditions: 36 m×2=72 metres36\text{ m} \times 2 = 72\text{ metres} (240 feet240\text{ feet}).

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1
Determine the baseline stopping distance at 40 mph40\text{ mph} under normal, dry conditions.
Thinking distance is 12 metres12\text{ metres} (40 feet40\text{ feet}) and braking distance is 24 metres24\text{ metres} (80 feet80\text{ feet}), giving a total dry stopping distance of 36 metres36\text{ metres} (120 feet120\text{ feet}).
Official Highway Code calculations split total stopping distance into thinking distance and braking distance.
2
Apply the environmental multiplier for wet weather conditions.
36 metres×2=72 metres36\text{ metres} \times 2 = 72\text{ metres} (120 feet×2=240 feet120\text{ feet} \times 2 = 240\text{ feet}).
The Highway Code explicitly states that stopping distances in wet weather are at least double those on dry roads due to reduced tyre grip and increased risk of skidding.

Anahtar Kavram

Highway Code stopping distances at speed and the doubling rule in wet conditions
Tahmini Süre:1m 0s
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Stopping Distances

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