The influence of road traffic noise on sleep

Abstract

The influence of road traffic noise on the sleep of adults and 6–11 year old children was studied by using electrophysiological methods. Young adults, unaccustomed to traffic noise, were disturbed by continuous and intermittent traffic noise at 45 dB(A). No sleep disturbances were found for continuous traffic noise at 36 dB(A). Car passages with a peak noise level of 55 dB(A) caused awakenings. The equivalent sound pressure level ( L eq ) did not correlate with sleep disturbance effects. A better noise dose description was found in the number of vehicles per night that made most noise. Children wer about 10 dB(A) less sensitive than adults to awakening reactions, and even less sensitive with respect to disturbances of REM sleep and deep sleep. Total habituation to road traffic noise did not occur, even after at least one year of exposure. Sound reduction in the bedroom induced increased amounts of deep sleep for adults and reduced falling-asleep time for children. Road traffic noise during the first hours of a night's sleep tended to disturb sleep more than when it ocurred later in the night, the main effects being a reduction of the total amount of REM sleep during the night and an increased duration of intermittent wakefulness during the hours of exposure.