Studying the Effect of Roughness of Wet Road on Critical Speed of Vehicle

Hydroplaning is one the most dangerous phenomena which effect on the safety of driving cars on wet roads, then, the critical speed of slipping cars is an important parameter in the hydroplaning ,and depends on the properties of the following three parameters: tires, water layer and road surface. The road texture is the main property of road specifications which affect directly on the critical speed of the vehicle. In the present work, the properties of road roughness and influence of surface texture on critical speed of vehicle are studied with variation of the following parameters: thickness and dynamic viscosity of water on the road surface and the vehicle load. The results showed that increasing the road surface roughness and the vehicle load both has a appositive influence on the critical speed (increase)of the vehicle, while increasing the dynamic viscosity and thickness of the water layer on the road surface has a negative influence on the critical speed (decrease) of the vehicle