What Makes Pavements Slippery?

Pavements, no matter what their construction and surface features, provide no traction or skid resistance when they are covered with a deep layer of water. Pavement design and other factors inhibiting or promoting hydroplaning are discussed, as are possible remedial measures. This leads naturally into a review of the pavement surface features that control the reduction of skid resistance with speed. The polishing of pavement surfaces and those of aggregate particles is discussed in the light of present knowledge and practices. Finally, the problems which the future might bring and the options for their solution are highlighted.