Dense fog affected Flevoland on Tuesday, while the KNMI issued a code-yellow warning for most of the country until noon. The weather institute defined dense fog as visibility of less than 200 metres and advised motorists to drive more slowly, keep greater distances and account for delays and dangerous situations.

The CBR said dipped headlights are mandatory when visibility is poor, including in fog, but that the use of fog lights is not mandatory. Front fog lights may be used when visibility is less than 200 metres, while rear fog lights may be switched on only below 50 metres. Drivers were advised to check the distance using roadside hectometre markers, ensure all lights work and know how to operate them manually, since automatic lighting may not function properly in fog. The CBR also advised considering whether a journey could be postponed, particularly when visibility is below 50 metres.