Abstract
Three series of psycho-acoustical experiments are performed to investigate the difference between the annoyance of road traffic noise evaluated in the field and that in the laboratory. The experiment I is carried out near actual road and subjects are imposed to dictate Chinese characters and instructed to evaluate annoyance of the noise that comes from the road. The experiment II is carried out in the same way but in the laboratory and the noises, which are recorded on magnetic tapes during the experiment I, are used as stimuli. In the experiment III the video images, which are also recorded on video tapes during the experiment I, are added to the stimuli. The experimental results show that L_<20>, L^^-+_σ, L_<eq> are fairly good indices of annoyance of road traffic noise evaluated in the field as well as in the laboratory. But the annoyance of noise evaluated in the field is smaller than that in the laboratory. The differences of them correspond to about seven to nine dBA in L_<eq>. The annoyance of noise when both sound and video images are used as stimuli can be predicted by L_<eq> and the factors derivated from factor analysis of the impression of environment near road. This fact shows that visual information as well as audio information of noise is a very important factor for the evaluation of annoyance of road traffic noise.
