A dry cement road is a diffuse reflector. When it rains, the water fills in all the little holes and cracks in the cement road and it becomes a smooth regular reflector. At night, when you are depending on the light from your headlights to show you the lines on the road, a wet road becomes much darker and it is more difficult to see the lines. Explain why this occurs.

Because of reflection of light away from the marking

Explanation:

It is because the light from a vehicle falls on the road and its markings which then gets illuminated as light is reflected only in one direction.

But in case when the road is wet, light of vehicle reflects in different directions away from the markings on the road and hence they do not illuminate.

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