Abstract
Friction on a wet road surface is highly dependent on macro and micro texture of surfacing. A good macrotexture improves drainage and together with a good microtexture gives good friction characteristics even at high speeds. Initially, surface dressing has very rough texture but this is soon abraded in winter. Macrotexture can also deteriorate in summer if bleeding occurs. Microtexture depends on crystalline structure of aggregate. Tyre studs create a good microtexture in winter but this is polished by summer tyres. In winter also friction can vary due to textural properties of wearing course. Open textured surfacings have lower friction in winter than closed textured ones.