Comparison of Longitudinal Unevenness of Old and Repaired Highway Lanes

Abstract

Remixing of the wearing course in the high-speed lane of a freeway resulted in a new road surface that, compared with the old surface in the adjacent low-speed lane, was perceived as a bumpy ride by road users, as well as by the road agency and the paving contractor. In this paper, the unevenness of the longitudinal road profiles of the old and the new (remixed) surfaces are analyzed and compared. The comprehensive analysis was conducted with statistical and signal processing tools. The probability density function (PDF), power spectral density (PSD), autocorrelation function, coherence, and occurrence of local obstacles in both lanes were evaluated and mutually compared. The profiles were quantified with commonly used indicators of road unevenness. The paper documents some disadvantages of the International Roughness Index (IRI) and advantages of road elevation power spectral density to reflect the ride quality of road profiles.