Evaluation of road roughness based on multi-fractal theory

The paper investigates a novel evaluation method of road roughness to overcome the shortages of the current used road roughness indices which cannot fine depict the characteristics of the road locally. Multi-fractal theory is employed to systematically research into appraising the road profile, which provides obvious multi-fractal characteristics. But the results of road surface simulation in each grades based on Fourier inverse transformation show there is no unique relation between multi-fractal spectral width and road roughness in different grades. However, in logarithmic distribution diagram, the vertical axis of the road intercept which have the same multi-fractal spectral width was different. Experimental results proved the IRI and multi-fractal spectrum width values are complementary to describe the road roughness. We proposed to signify the road roughness by combining multi-fractal spectral width and the IRI as a supplement of current indices.