Correlations and Analyses of Longitudinal Roughness Indices

ABSTRACT This paper analyses some of the most widely used indices for the characterization of longitudinal roughness. Measured longitudinal profiles available in the Long-Term Pavement Performance (LTPP) program database were used. A total of 207 pavement sections, in 42 States of the USA, were used in these analyses. Using a suitable software, the International Roughness Index (IRI), the Standard Deviation of longitudinal roughness (σ) and the Root Mean Square of Vertical Acceleration (RMSVA) with different base lengths were computed for every measured longitudinal pavement profile. Linear regression analyses between the IRI and σ statistics produced a very high correlation (R2=0.93). Multivariate regression between IRI and the RMSVA also showed a high correlation (R2=0.96) for base lengths of 1.0 m and 3.5 m. On the other hand, when the RMSVA and σ statistics were analyzed, it was observed that all regressions including a RMSVA with the base length of 1.5m presented a nearly perfect correlation (R2≅1.00...