In normal dry conditions, a passenger car travelling at 30 mph has an average total stoppi… — UK Driving Theory Test

In normal dry conditions, a passenger car travelling at 30 mph has an average total stopping distance of 23 metres (comprising 9 metres thinking distance and 14 metres braking distance). When travelling at this speed on a road surface made wet by rainfall, what is the minimum total stopping distance, in metres, that the driver must allow according to The Highway Code?

Answer: 46 metres

Answer

46 metres

According to The Highway Code (Rule 126), stopping distances on wet roads are at least double those required on dry roads because surface water reduces tyre grip and increases braking distance. Since the dry stopping distance at 30 mph is

23\text{ metres}

, the minimum stopping distance in wet weather is

23 \times 2 = 46\text{ metres}

Step-by-Step Solution

Identify the standard baseline stopping distance under dry conditions at 30 mph

Total dry stopping distance is

23\text{ metres}

(

9\text{ m}

thinking distance +

14\text{ m}

braking distance)

The baseline dry stopping distance provides the reference value established in The Highway Code.

Determine the required safety margin multiplier for wet weather conditions

The stopping distance multiplier is

2

The Highway Code Rule 126 states that overall stopping distances in wet conditions are at least double those on dry roads.

Calculate the minimum wet weather stopping distance

23\text{ m} \times 2 = 46\text{ metres}

Doubling the total dry stopping distance gives the required safe margin in wet weather.

Key Concept

The Highway Code stipulates that overall stopping distances in wet conditions are at least double those required on dry roads.

Estimated Time:1m 0s

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