A questionnaire survey was conducted to investigate the effects of noise and vibration on the residents living near trunk roads. Psychiatric disorder of the residents was evaluated using the 28-item General Health Questionnaire (GHQ-28). In our previous study, a significant dose-response relationship was detected between the psychiatric disorder identified by GHQ-28 and the exposure to noise and vibration from road traffic.
In this study, a further analysis was conducted to examine the relationship between the psychiatric disorder and disturbances of daily life caused by the exposure. The analysis revealed that the effects on the mental health were mainly due to sleep disturbance caused by the vibration, and that a reduction in the vibration levels by approximately 5 decibels would mitigate the mental health effects as well as the sleep disturbance. The analysis also suggested that the vibration measure of LV10 for road traffic would be inappropriate to evaluate sleep disturbances and mental health effects.