At very low temperatures, ice is dry and is similar to a micro-rough surface (micro-roughness of 10 μm) and produces micro-indentation and molecular adhesion. However, in micro-roughness, asperities are very small and easily become flooded. At temperatures between -5 and 0°C, the pressure of the tire on the road causes slight surface melting of the ice, which is in turn covered by a thin film of water. The ice is then like a flooded micro-smooth surface.
