Chapter 9: Skid resistance

Skid resistance is a measured parameter that characterises the contribution that a pavement surface makes to the level of friction available at the contact patch between a surface and a vehicle tyre or pedestrian. Friction measurements need to replicate the actions of acceleration, braking and cornering manoeuvres of traffic, or the slip potential for pedestrians. The basic principles are set out here.

If a body of weight P (= mass (M) × acceleration due to gravity (g)) is at rest on a surface, all the forces acting on it are vertical. If a horizontal force F is applied to try to move the body, the magnitude of this force must be sufficient to overcome the resisting effects of friction. If the coefficient of friction is 1.0, then F = P.