Road traffic noise is one of the major environmental issues worldwide. In Japan, annual reports by the Ministry of the Environment indicate that the achievement rate of the environmental quality standard for noise has shown little improvement in recent years. To address this issue, traffic noise prediction models such as CNOSSOS-EU in Europe and ASJ-RTN in Japan have been developed. However, the vehicle noise source models used in these systems are based on fixed formulas and do not reflect recent regulatory changes, including the three-phase tightening of vehicle noise limits from 2016 to 2027. Therefore, updated source models that incorporate these regulatory progresses are required. This study proposes a simplified method for constructing vehicle noise source models that take into account differences in regulatory categories and legal limits, based on the results conforming to UN Regulation No. 51 03 series. The model enables realistic estimation of vehicle noise emissions and facilitates the analysis of key noise contributions. Its accuracy was validated by comparing predicted values with actual measurements of road traffic noise levels (LAeq). The results confirm the model’s applicability and effectiveness as a tool for traffic noise analysis.
Shirahashi et al. (Wed,) studied this question.