Assume no variable speed sign controls. Which conditions require the applicable maximum to be reduced by 50 percent under the national rules? Select all that apply.

Explication

An icy surface, weather restricting sight to no more than 100 metres, and snow accumulation of at least 20 millimetres trigger the half-speed reduction. A merely wet road is governed by the smaller 20 percent reduction, so wetness alone does not belong in the more severe group.