The Little Book of Tire Pavement Friction : Pavement Surface Properties Consortium

Frictional properties of pavements play a significant role in road safety as the friction between tire and pavement is a critical contributing factor in reducing potential crashes. When a tire is free rolling in a straight line, the tire contact patch is instantaneously stationary and there is little or no friction developed at the tire/road interface, although there may be some interactions that contribute to rolling resistance. However, when a driver begins to execute a maneuver that involves a change of speed or direction, forces develop at the interface in response to acceleration, braking, or steering that cause a reaction between the tire and the road (called friction) which enables the vehicle to speed up, slow down, or track around a curve. To reduce the number of fatalities, injuries, and properties damage due to car crashes, the Federal Highway Administration (FHWA) issues guidance to highway agencies in management of pavement surface friction on roadways (FHWA 2010)