| The conventional evaluation index of rutting、 the rut depth、 has a drawback in that influence of vehicle behavior on riding quality is hardly obtained because it simply depends on the maximum displacement in the measured profile with unlimited wavelengths. The objective of this study is to develop a new evaluation index of rutting. Unlike the rut depth、 the new index intends to estimate the ride quality of road vehicles based on the wavy characteristics of the profile. The continuous wavelet analysis shows that wavelengths from 0.33 to 0.67m identify the wavy characteristics corresponding to the vehicle motion caused by the lane-change maneuver in the rutting. Above all、 a wavelength of 0.4m seriously reduces the riding comfort. According to the analysis、 the new index is calculated from the transverse profile adjusted for emphasizing the wavelength of 0.4m by a band-pass difference filter、 thus is called “the adjusted rut depth”. Mathematically、 it is defied as the elevation difference between the top and the bottom of the filtered profile. As the result of regression analysis、 the adjusted rut depth closely correlates with the ride quality rating value based on the vehicle dynamics. The index helps to overcome the shortcomings of the rut depth by allowing road administrators to predict the ride quality depending on the profile characteristics within the limited waveband. These findings contribute to the accuracy improvement in user-oriented monitoring strategy of road surfaces. |
