Sleep disturbance by traffic noise: an experimental study in subjectsʹ own houses using a portable CD player

The current study investigated the effect of noise on sleep in subjectsʹ own houses using recorded traffic noises. A railway noise and two kinds of road traffic noise differing in level-fluctuations were used as stimuli. Subjects were exposed all night to the artificially controlled stimuli for 10 days through a portable compact disc (CD) player. The effect of noise on sleep was judged in three ways, namely whether the subject had switched off the CD player, a self-declaration of the subject based on a questionnaire, and the amount of arm movement of the subject during the night as measured by an actigraph. The results of the analysis of the self-declaration data showed that the thresholds where sleep disturbance began were 40–45 dB in L Aeq , 1 h for road traffic noise and about 35 dB for railway noise, which corresponded to 50–55 dB in L A , F max of each train noise event. The results of the analysis of the actigraphy data showed a rapid increase in the incidence of mid-sleep awakening at sound pressure levels higher than 50 dB, L Aeq , 1 m for railway noise. However, neither of the road traffic noises showed such a tendency, as long as the sound pressure level was less than 55 dB, L Aeq , 1 m .