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Road noise

The automotive industries of Japan, United States and Europe are persisting in their efforts to further abate noise from automobiles. JARI examines noise measuring methods and make predictions of the effects of noise regulations by applying computer simulation. The results of these studies have been employed as basic reference data for the drafting of Japanese and international regulations for automotive noise. Moreover, our test data have been utilized in the global discussion to make the quiet electric vehicles recognizable to pedestrians by adding an artificial sounding function.

(1) International harmonization of noise test methods

To achieve an effective reduction of automotive noise, noise generation is assessed using a test method that reflects the on-road running conditions of vehicles, and  countries are working together to develop such a noise test method. JARI supplies its test data and analytical results to ISO and UN/ECE/WP29/GRB for the drafting of an international noise regulation.

Vehicle noise testing

(2) Prediction by computer simulation

To introduce a comprehensive traffic noise reduction program, it is imperative to predict the effect of a conceived noise reduction program in advance. JARI aims to make reliable noise predictions using its original simulation method that combines a simulation of realworld traffic flow and a sound pressure waveform synthesizing technique.

JARI traffic noise simulation model