08/11/2026
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Yellow Weather Warning for Fog – Are Your Lights On?
With a yellow weather warning for fog in place today, we're reminding drivers not to rely solely on their vehicle's automatic lighting systems.
Daytime Running Lights (DRLs)
Most modern vehicles are fitted with daytime running lights, which automatically illuminate when the vehicle is switched on.
These lights are designed to make your vehicle more visible to other road users during daylight hours. However, they are not designed to illuminate the road ahead.
Crucially, on many vehicles, daytime running lights do not activate the rear lights. This means that while your vehicle may be visible from the front, it could be extremely difficult for drivers approaching from behind to see you in foggy conditions.
Automatic Headlights
Many vehicles also have an automatic headlight setting, which uses sensors to detect changes in ambient light.
The problem is that fog can significantly reduce visibility without making it dark enough to trigger the automatic headlights.
As a result, your vehicle may continue running on daytime running lights alone, leaving your rear lights switched off.
What Should You Do?
If you're driving in fog or poor visibility, check that your dipped headlights are switched on rather than assuming your automatic system has activated them.
Under the Highway Code, you MUST use headlights when visibility is seriously reduced, generally when you cannot see for more than 100 metres.
Front and rear fog lights may also be used when visibility is seriously reduced, but remember to switch them off when visibility improves to avoid dazzling other road users.
Reduce your speed, increase the distance between you and the vehicle in front, and allow extra time for your journey.
Don't assume your lights are on just because your dashboard is illuminated.
Stay safe on the roads.
Leicestershire Fire and Rescue Service – Castle Donington Station
