The slipperiness is caused by the freezing of wet road sections and local winter showers. The risk of accidents on roads, cycle paths and pedestrian paths is therefore much greater. In addition, traffic may also be affected by fog banks in the morning.
People in traffic are advised to be extra careful and adjust their speed. The ANWB has a rule of thumb: halve your speed and double the distance to the vehicle in front if it is slippery. They recommend looking far ahead on the road and accelerating slowly.
The yellow warning code applies from 8 a.m. to 11 a.m. The situation is a lot more dangerous in the provinces of Groningen and Friesland; Code orange has been issued there.