In autumn, fallen leaves or soil and mud from agricultural machines can cause the road to be slippery, especially during and after rain.
During autumn and spring it can sometimes be so cold that rain and melted snow freeze during the evening and night, resulting in so-called slippery spots. The risk of slippery spots forming is especially great in shady areas and on bridges and viaducts.
Frost slipperiness can also be formed on snow-free roads during autumn and spring when the air's moisture freezes on the road surface. Frost slipperiness is most common at dawn and early in the morning after a cold and clear night. Fog can also cause frost slipperiness.
Drive carefully and be prepared for slippery roads after sudden temperature fluctuations and after cold evenings and nights.