Part 2 of 4 in Car lighting & Dashboard
Fog lights: when may you use them?
Front fog lights may only be used when visibility is seriously reduced due to fog, snow or heavy rain. It is never mandatory.
Written by Chris Prosman Reviewed by Dirk van Zuijlen
Updated Reviewed on 4 min read
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Front fog lights may be used when fog, snow or rain makes it very hard to see. The rear fog light is only allowed in fog or snow, when you can see less than 50 metres ahead.
Video explanation
When should you use fog lights?
In short:
- Front fog lights: when fog, snow or rain seriously reduces visibility.
- Rear fog light: only in fog or snow, and only when you can see less than 50 metres. Never in rain.
| Symbol | When may it be on? | For whom? |
|---|---|---|
 | Fog, snow or rain seriously reduces visibility. | For you: you see the road better. |
 | Only in fog or snow and with less than 50 metres visibility. | For others: traffic behind you sees you sooner. |
Are fog lights mandatory?
No. You may use them, but you never have to. Dipped beam is fine in fog too. Not every car has front fog lights: they are extra equipment.
Front fog lights: the rules and the 200 metres
Front fog lights are allowed when fog, snow or rain seriously reduces visibility. A light shower or some haze is not enough.
In driving lessons you often hear: front fog lights below 200 metres of visibility. That is a handy rule of thumb. The law has no fixed 200-metre limit. It only says that visibility must be seriously reduced.
Driving with front fog lights? Then your dipped beam does not also have to be on. Your rear lights and number plate light must be on. Front fog lights together with dipped beam are allowed too. Switch the fog lights off as soon as visibility improves.
Rear fog light: when may you turn it on?
The rear fog light is only allowed with less than 50 metres visibility because of fog or snow. Can you see 50 metres or more? Then it stays off.
It is a very bright red light. In better visibility it dazzles the driver behind you. Using it is never mandatory.
Can you use fog lights in the rain?
Front fog lights yes, if the rain seriously reduces visibility. The rear fog light never, not even if the rain cuts visibility below 50 metres. Use dipped beam then, and front fog lights if you like.
How do you judge visibility? Count the hectometre markers
Hectometre markers stand along the road every 100 metres. Are you at a marker and can you see the next one? Then you can see at least 100 metres. The rear fog light stays off.
Can you not see the next marker? Then you still do not know if visibility is below 50 metres. It might be 70 metres.
In fog, slow down and keep more distance. You must be able to stop within the distance you can see. Full beam does not help in fog: the light reflects back. See full beam.
Fog light symbols: front and rear
Both fog light symbols have a wavy line through the light rays. This is how you tell them apart:
- Front fog lights: green symbol, rays to the left.
- Rear fog light: orange symbol, rays to the right.
The light on your dashboard has a different colour from the lamp itself. The rear fog light outside is bright red, even though the symbol inside is orange.
How do you turn on your fog lights?
Look for the button or switch with the same symbol. It is often next to the light switch or on the stalk. In many cars the button only works when your lights are on as well. Check the manual for how it works in your car.
Sources: RVV 1990, articles 32, 34, 38 and 41, and Dutch government guidance on vehicle lighting.
Practise like the exam
Example questions like in the CBR exam
Real questions from the Theorio app. You can expect similar questions in your CBR exam.
Question 1 of 5
The fog light is used exclusively in bad weather (rain, fog, snow) and when visibility is less than 200 meters.
Which symbol indicates fog lights?
Tap the answer you think is right.
The rear fog light is used only in very limited visibility (less than 50 meters) due to dense fog or snow, never in rain.
Which symbol indicates fog rear lights?
Tap the answer you think is right.
The visibility is 30 meters. You are driving with your fog rear light on, is that allowed?
Tap the answer you think is right.
Which one can you turn on in the rain, with visibility less than 50 meters?
Tap the answer you think is right.
You can read the next 3 hectometer signs. You are driving with fog lights on, is that allowed?
Tap the answer you think is right.
Answers and explanations for the example questions
Question 1: Which symbol indicates fog lights?
Correct answer: Symbol C
Symbol C stands for fog light. Use this exclusively in bad weather and when visibility is less than 200 meters. Fog lights improve your visibility in dense fog 🌫️
Question 2: Which symbol indicates fog rear lights?
Correct answer: Symbol D
Symbol D is the fog light. Only switch it on in visibility of less than 50 meters, but never in rain to avoid glare. Fog light is exclusively for extreme conditions 😶🌫️
Question 3: The visibility is 30 meters. You are driving with your fog rear light on, is that allowed?
Correct answer: Yes
Is the visibility less than 50 meters? Then the fog rear light is allowed for extra visibility. Fog rear light improves your visibility in extremely short visibility distances 🌫️
Question 4: Which one can you turn on in the rain, with visibility less than 50 meters?
Correct answer: Fog lights
With visibility less than 50 meters in the rain, fog lights are allowed, but fog tail lights are not. Fog lights help without unnecessary glare 💧
Question 5: You can read the next 3 hectometer signs. You are driving with fog lights on, is that allowed?
Correct answer: No
At 300 meters (1 hectometer sign is 100 meters) visibility, fog lights are unnecessary and prohibited. They are only allowed under 50 meters visibility. Fog lights are strictly for fog with visibility less than 50 meters ❌
FAQ
Frequently asked questions
Short answers to questions that often come up on this subject.
May you use the rear fog light in heavy rain?
No. The rear fog light is only allowed in fog or snow with visibility below 50 metres, never rain. Front fog lights are permitted if rain seriously impairs visibility. Dipped headlights remain an option.
Are front fog lights compulsory in fog?
No. Front fog lights are permitted when fog, snow or rain seriously impairs visibility, but are not compulsory. The law specifies no fixed 200-metre threshold. Dipped headlights remain an option; front fog lights do not require dipped headlights additionally. Rear and number-plate lights must still illuminate.
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