Indoor discomfort from ground transportation traffic vibration and noise—Comparison between Vietnamese and Japanese young participants

This research investigated discomfort responses to combined whole-body vibration and noise in Vietnamese and Japanese participants. Twenty stimuli, comprising five vibration magnitudes and six noise levels induced by ground transportation traffic (road traffic, Shinkansen railway, and conventional railway), were applied. Combined effects on discomfort were observed when vibration and noise had comparable impacts. Although Japanese participants reported greater discomfort, the increase because of combined effects did not differ significantly between groups. Logistic regression with an interaction term provided a statistically significant but marginal improvement in modelling "percent highly uncomfortable" responses, whereas including participant group significantly enhanced the model's goodness-of-fit. Both multiple linear regression and root-sum-of-squares models effectively modeled discomfort, performing better when applied to data with comparable vibration and noise effects than to all combined stimuli. These findings highlight the importance of considering cultural differences and stimulus comparability in modelling human responses to environmental vibration and noise.