Modeling and Analysis of Truck Hydroplaning on Highways

Abstract

The widely adopted NASA hydroplaning equation has been able to predict closely the hydroplaning speed of passenger cars on a wet pavement. However, field observations and experimental studies have found that the equation cannot explain the hydroplaning behaviors of trucks. According to the NASA equation, trucks hydroplane only at a speed much higher than the normal range of travel speeds on highways. However, this conclusion is not supported by real-world experience and field tests. In addition, field observations and experimental studies have found that lightly loaded trucks are more prone to hydroplaning than heavily loaded ones. This phenomenon cannot be explained by the NASA equation, which states that, regardless of the magnitude of wheel load, hydroplaning speed is the same if tire inflation pressure remains unchanged. To the authors’ knowledge, no studies have demonstrated theoretically or analytically why trucks behave differently from passenger cars in their hydroplaning behaviors. Using the technique of three-dimensional finite element modeling, this paper analyzes the problem of truck hydroplaning with an analytical simulation model based on hydrodynamics theory. The formulation of the model is described, and the computed results are validated against past experimental studies. The effects of tire inflation pressure, footprint aspect ratio, and truck wheel load on truck hydroplaning speed are also examined to help explain the different hydroplaning behaviors of trucks and passenger cars.