Pavement roughness index impact for specific wavebands and causative factors

This study quantified roughness for individual wavebands in the long wavelength range in pavement longitudinal profiles. Particularly, the roughness was related with quantified plausible factors associated with those wavebands. Root Mean Square (RMS) roughness defined under the Power Spectral Density (PSD) profile in the frequency domain was used as a quantified index that can reflect detailed roughness information for a specific waveband. A method to interpret the quantified roughness in terms of the International Roughness Index (IRI) was also developed. It was demonstrated that the RMS roughness evaluated in individual wavebands under the PSD function can be technically interpreted in terms of IRI. Thus, the interpreted IRI could be directly explained by the quantified plausible factors. It was concluded that the demonstrated method can contribute to improved roughness prediction models the Mechanistic-Empirical Pavement Design Guide (MEPDG) with smoothness characteristics in detailed wavelengths underpinnings in future generations of pavement design models.