Comparison of sound emission models for road vehicles in Japan and European countries

Abstract

The road traffic noise prediction model "ASJ RTN-Model," which has been developing by the Research Committee in the Acoustical Society of Japan, is used widely in environmental impact assessment in Japan. In the latest model, ASJ RTN-Model 2018, several coefficients of the calculation equation for the A-weighted sound power level of road vehicles were updated. In European countries as well, various prediction models such as Nord, Harmonoise, and CNOSSOS-EU have been published. Since 2018, the specific noise emission, which can be incorporated into CNOSSOS-EU, was proposed in several countries: CNOSSOS-NL, -FR, and sonROAD. Also, the emission values in CNOSSOS-EU were replaced in 2021. Thus, the values of noise emission and its frequency characteristics were compared between these prediction models using the immission values calculated considering the effects of a barrier and the ground surface. The results demonstrated that a valid relationship exists between the emission values in ASJ RTN-Model 2018 and those in European models. Additionally, in the prediction assuming a reflective ground such as in urban areas, the differences in frequency characteristics of noise emission between the models will be negligible.