Evaluation of Vehicle Braking Performance on Wet Pavement Surface using an Integrated Tire-Vehicle Modeling Approach

Abstract

Water film on a pavement surface greatly increases vehicle accident rates on rainy days. The simple use of a lower friction coefficient to evaluate the vehicle braking performance oversimplifies the contact mechanism between the tire and the pavement, and the use of a pure single tire model simulating hydroplaning was not able to reflect actual vehicle braking-cornering behaviors. This paper proposes an integrated tire-vehicle model to evaluate vehicle braking performance based on Persson’s friction theory, a tire hydroplaning finite element model, and a vehicle dynamic analysis. The friction coefficients between the tire and the pavement were calculated theoretically from the pavement surface morphology and the tire rubber properties; the tire hydrodynamic forces were obtained mechanistically from the hydroplaning model with different water film thicknesses and were used as inputs for calculating the braking distances in a vehicle model. The calculated friction coefficients and braking distances were verified using the field test results. A case study was conducted to illustrate the approach and evaluate the vehicle braking performance on straight and curved road sections. The results show that both longitudinal braking distances and lateral slip distances should be considered in the evaluation of vehicle braking performance.