Tyre/road noise measurements on public roads were conducted in order to investigate the effect of road surface condition on vehicle pass-by noise on public road of Japan. Since applying the CPX method to evaluate public road of Japan must be subject to domestic regulations and is considered to pose some safety risks, a quasi-CPX method was employed after its vehicle noise evaluation validity had been confirmed by road tests on a test track. The tyre/road noise measurements by the method on public roads were performed on 2 routes including 3 types of road surfaces - dense asphalt (DAC), porous asphalt (PAC), and double layer porous asphalt concrete (DLPAC) surfaces. As a result, it was confirmed that the level of tyre/road noise of each road surface type spreads to the range of 4 to 9dB, and that the spread of DLPAC pavement seems to be wider than other surface types.
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