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Difficulty: MediumFog and Poor Visibility

When driving in dense fog, switching your headlights from dipped beam to main beam increases forward visibility by projecting light further through the fog.

Answer: Answer

Answer

False
The statement is false. Main beam headlights aim high and reflect off the millions of tiny water droplets suspended in fog. This creates a wall of dazzling glare that reflects back into the vehicle, drastically reducing forward visibility rather than improving it. Dipped headlights must be used to keep the beam angled downward onto the road surface.

Step-by-Step Solution

1
Examine how high-angle light beams interact with dense atmospheric fog
Main beam light strikes suspended moisture droplets and scatters backward toward the driver.
This reflection creates a blinding white glare that conceals road hazards and reduces visible distance.
2
Determine the proper vehicle lighting selection in accordance with UK Highway Code rules for fog
Dipped headlights should be selected because their downward angle illuminates the road surface with minimal light reflection.
Dipped beams aim below the driver's direct line of sight, preventing backscatter and allowing auxiliary fog lights to work effectively if visibility falls below 100 metres.

Key Concept

Headlight beam angle and reflective backscatter in fog
Estimated Time:45s
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Topics

Fog and Poor Visibility

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