摘要：Internal noise was greater than external noise at Aoba Elementary School in Shizuoka and the Elementary School attached to Shizuoka University. In front of these school's gates, 156 cars per hour passed and 160 noises per hour were given. On the other hand, in front of a gate of Eujieda-kita High School along the state road No. 1, 750 cars per hour passed and the continued time of noise by a car was 9.7 seconds, then the product was 122 sec. car noise per minute : it meaned that the pupil was continuously annoyed by noise at the school. As the result of frequency analysis, audiospectrum of noise in the class rooms along the road was similar to that of noise by car. It was found that the sound level by car was calculated from the traffic volume of car (cars/min.) by regression equation because the sound level had a significant correlation with the traffic volume in both A and C range.
