FogWallonia
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230. Fog
Fog can greatly reduce visibility and make it difficult to judge speed, distance and the position of other road users. Drivers should reduce speed, increase their following distance and use the appropriate lights without dazzling others. Avoid relying only on the vehicle ahead as a guide, and be prepared for sudden changes in visibility. When fog is very dense, stopping in a safe place may be the best option.
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Do you have to reduce your speed in fog in Belgium?
Yes. Belgian traffic rules require drivers to adapt their speed to visibility, weather, road conditions and traffic. The posted speed limit may therefore be too fast when visibility is reduced by fog.
When must rear fog lights be used in Belgium?
Under the current Belgian rules, rear fog lights must be used when fog reduces visibility to less than approximately 100 metres. They may not be used in other circumstances unless another permitted condition applies.
May front fog lights be used in fog in Belgium?
Yes. Under the current rules, front fog lights may be used in fog. They may replace the dipped or main-beam headlights or be used together with them.
Do normal vehicle lights also have to be used in fog in Belgium?
Yes. The prescribed vehicle lights must be used whenever visibility is sufficiently reduced. Fog lights are additional or alternative lighting under the conditions allowed by the traffic rules.
Will the fog-light rules change under Belgium’s new Road Code?
The basic rule remains similar. Under the new Code of the Public Road, rear fog lights must be used and front fog lights may be used when fog reduces visibility to less than approximately 100 metres. The new code uses the same approximate 100-metre threshold for heavy precipitation as well.

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