PROBLEMS IN ROAD SURFACE MODELING

The properties of real roads along the lateral axis cannot not be adequately explained with the classic model of the isotropic road. With a realistic assumption of spatial invariance (homogeneity), a more general surface model has been formulated and compared with the experimental data. A good match of measurements and "theory" has been achieved. A simple parametric approximation is developed for the coherence function on the basis of the extended unevenness model. In addition to the undulation exponent of the road surface and the track width, the curve is characterized by three other key figures. The adaptation to the experimental data results in comparatively small yet justifiable parameter intervals. Due to the further development of filter methods for the synthesis of random irregularities, a model family is now available which facilitates a satisfactory balance between model accuracy and numerical complexity for most applications. The main difficulties would appear to lie in the formulation of a consistent tyre-road interface which is also acceptable from the point of view of computation time.