Sleep disturbance due to road traffic noise: A socio-acoustic survey using Lnight estimated from noise maps

A socio-acoustic survey was conducted in Kanagawa Prefecture, Japan, to investigate the relationship between road traffic noise and sleep disturbance. Nighttime noise exposure (Lnight) was estimated using the ASJ RTN-model 2013 and categorized in 5 dB intervals from 30 to 80 dB. Residents reported the frequency of five sleep-related symptoms attributed to road traffic noise. Participants experiencing any symptom ≥3 times/week were classified as highly sleep disturbed (HSD), and those with 1–2 times/week as sleep disturbed (SD). Multiple logistic regression analysis revealed that both Lnight and noise sensitivity were significantly associated with SD (p = 0.006, p < 0.001), whereas only noise sensitivity significantly predicted HSD (p < 0.001). Stratified analysis showed a clearer exposure–response trend among residents in detached houses than in apartments. Compared to a previous meta-analysis of Japanese surveys, the proportion of HSD at the same Lnight levels was approximately 10% higher, possibly due to a broader definition of sleep disturbance. These findings highlight the continued public health relevance of road traffic noise, the influence of individual sensitivity, and the need for standardized sleep disturbance measures in noise surveys.