Abstract
The actual state of road traffic noise in Kitakyushu was investigated. As a result, noise near trunk roads often exceed Japanese environmental quality standard. Even in the daytime, only 11 per cent of ovservation points are less than the standard. The excess amounts depend on area, time and number of lane. For example, in the residential area the 30 percentile excess amount is about 10-16dB (A), and that in another area is 2-8 dB (A) except night. And traffic intensity contribute much to the excess amounts. But the contribution of the mixture of heavy vehicles decrease because regulatory standard to noise source become strict gradually.
