This paper describes a laboratory sleep study with an exposure situation corresponding to a dwelling close to a railway. Both noise and bed vibrations were generated for passing trains, and the sleep quality of the test subjects was evaluated using questionnaires before and after sleep. A total of 21 test subjects slept five nights in the laboratory, and three different exposure situations were presented in a randomized order after two nights for habituation. The three exposures were combined from two noise levels and two vibration amplitudes; one with high noise levels and strong vibrations, one with lower noise levels and strong vibrations and one with high noise levels and weaker vibrations. The results indicate that the perceived sleep disturbance from noise increased with increasing vibration amplitude. There was no such interaction effect for perceived sleep disturbance due to vibrations, i.e. sleep disturbance due to vibrations was the same irrespective of noise level. These results suggest that it will not be sufficient to reduce the noise levels to protect from sleep disturbances, e.g. by sound insulating windows and noise barriers, if vibration levels are high. The vibration levels must also be addressed.
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