Prediction of wet-pavement skid resistance and hydroplaning potential

The current means of predicting the skid resistance of a wet pavement and the speed at which hydroplaning would occur are based on empirical models or relationships derived from experimental studies. These models and relationships are applicable only for the conditions specified, and extrapolations beyond the applicability range of parameters (e.g., vehicle speed, tire load, tire inflation pressure, water film thickness, and type of tire and pavement surface) are not advisable. Such restrictions could be overcome by developing an analytical model based on theoretical considerations. An analytical model also would provide a more in-depth understanding of the relative influence of different parameters. A three-dimensional finite element model is presented to predict wet-pavement skid resistance and hydroplaning speeds (i.e., wheel speed at which hydroplaning occurs) under different magnitudes of passenger-car wheel load, tire inflation pressure, water film thickness, and vehicle speed. The analysis shows that hydroplaning speed increases (i.e., hydroplaning risk decreases) with wheel load and tire inflation pressure but decreases with the depth of water film thickness. The skid resistance measured in terms of skid number decreases as the sliding-wheel speed or the water film thickness increases but increases with the magnitude of the wheel load and is affected marginally by the tire inflation pressure. Within the normal passenger-car operation range of each of the parameters, the hydroplaning speed is affected most by tire inflation pressure followed by water film thickness and is least influenced by the wheel load; the skid resistance is most influenced by sliding-wheel speed followed by water film thickness and wheel load and is least affected by the tire inflation pressure.