A method for characterization of the road surface with respect to its influence on tyre noise is presented. The method implies that the power spectral density (psd) of the road profile is measured for spatial frequencies between 2 and 1000 cycles/meter (corresponding to wavelengths 1-500 mm). Analysis has been made with a frequency resolution of approximately 2 cycles/meter, but the result indicates that in most cases octave band analysis is satisfactory. The method described does not give a complete description of the road parameters influencing tyre noise, but can only be considered as an important partial solution. By comparing frequency spectra from the road profile with tyre noise spectra it is shown that, for some of the tested tyre-road combinations profile spectra have a strong influence on tyre noise spectra. Besides practical and theoretical considerations of the proposed method, a survey of existing methods of road characterization with respect to tyre noise is made, as well as a short discussion on alternative and/or supplementary methods.
Abstract