Abstract
The relationship between surface damage ( the presence of ruts and undulations) and traffic safety is discussed. The characteristics of the road and the road surface may not show unsuspected changes for a controlled and safe traffic. The presence of ruts in the combination with waterlays can easily led to aquaplaning. Presence of waves can lend to a not well perceived contact tyre /road. A mathematical model is developed to determinate if the thickness of the waterlay by which almost no aqua.