A study of variables associated with wheel spin-down and hydroplaning. Paper presented at the 51th Annual Meeting Highway Research Board HRB, Washington, D.C., January 1972.

Vehicles operating on wet pavements suffer impairment of their steering and braking capabilities. Tests have shown that this condition worsens as the vehicle speed increases and at a critical ground speed the vehicular wheel is separated from the pavement by a layer of fluid and is said to be hydroplaning. This report uses wheel spin-down as a criterion for evaluating the wet weather properties of a Portland cement concrete pavement and a gravel seat coat pavement and considers the effects of water depth, tire inflation pressure, tire tread depth, and wheel load. Results are given.