Effects of nocturnal railway noise on annoyance: Dose-response relationships from a field study in comparison to nocturnal aircraft noise annoyance

Abstract

Annoyance from traffic noise is not only a problem in the daytime. Noise-induced sleep disturbances in the night may cause annoyance reactions, as well. In a laboratory and a field study examining sleep and annoyance from nocturnal aircraft noise conducted by the DLR Institute of Aerospace Medicine significant dose-response curves were found between nocturnal aircraft noise and annoyance. The present field study investigated the effects of nocturnal railway noise on sleep and annoyance of residents living in the vicinity of railway tracks in the area Cologne/Bonn (Germany). Acoustical measurements were carried out during nine consecutive nights at each site. Annoyance ratings were surveyed by questionnaires in the morning. Dose-response relationships between the acoustical parameters equivalent noise level (LAeq) and number of noise events (number of trains in general, freight trains, and passenger trains) and annoyance ratings were calculated. Annoyance increased significantly with the number of trains, particularly the number of freight trains, but in contrast to the field study regarding nocturnal aircraft noise only when the model was adjusted for moderating variables (subjective adaptation and length of residence). Annoyance increased non-significantly with rising LAeq. A comparison between the effects of the different traffic modes indicates lower nocturnal annoyance from railway noise than from aircraft noise at the same number of noise events. Furthermore, the data suggest that general annoyance judgements are mainly based on annoyance from traffic noise exposure during the day.