自動車交通騒音の評価方法に関する基礎的研究 (1) : 航空機騒音との比較

抄録

The two hearing tests were performed with the object of discussion of the applicability of Noise and Number Index (NNI) to the subjective rating of traffic noise in order to estimate the annoyance of traffic noise and aircraft noise by the same scale. In this case the NNI is calculated by using the number of traffic noise peaks heard while the NNI of the aircraft noise is calculated by using the number of flyovers. The noise samples were the traffic noise recorded at the side of the traffic road (Fig. 1a) and the series of aircraft noises recorded at the field in the vicinity of the airport (Fig. 1b &amp Table 5). Both noises were reproduced at the various NNI values (Table 2 &amp 6) in the testing rooms (Fig. 2 &amp 6). The subjects rated the annoyance of these noises on the six categories rating scale (Table 4) while calculating the simple arithmetical tasks (Table 3 &amp 7). Fig. 3 shows the results obtained from the hearing tests. The conclusions are as follows. 1) The annoyance of the traffic noise can be estimated by the NNI. In this case N is not the number of vehicles but the peaks of the traffic noise heard. 2) The NNI of the traffic noise is larger than that of the aircraft noise at the same degree of annoyance, and the difference is 6. 5 NNI, therefore the comparison between the annoyance of the traffic and the aircraft noise can be made by the NNI considering this difference in the case of the traffic conditions shown in Table 1. 3) The difference of the effects due to the traffic noise and the aircraft noise on the arithmetical tasks was hardly seen.