Assessment of Tire Noise on Concrete Pavement in California Highways

A 2-year initial study, recently completed in California, measured and compared tire–pavement noise levels with the onboard sound intensity method on existing concrete pavements. The study included 120 pavement subsections at 47 sites; most sections were measured twice in the 2 years. The surfaces encountered were classified into five texture categories: burlap drag, diamond ground, diamond grooved, longitudinally broomed, and longitudinally tined. The experiment was not balanced for age, traffic level, or climate region. The surfaces were further categorized as having new, aged, or worn-out texture. The differences within and between surface types were assessed for spectral content and overall sound intensity. The results revealed a large overlap in the onboard sound intensity levels between texture types. The quietest sections overall were measured on diamond ground surfaces. However, on the basis of the average noise level of the evaluated sections of each texture type, the longitudinally broomed surfaces as a group were the quietest, although they were represented by a small sample in the experiment. The study indicated that the sound intensity of concrete pavements in California ranged from about 99 to about 107 dB(A). The measured onboard sound intensity levels included the effects of joint slap, faulting, and sealant, if present, in addition to the texture.