Examining the relationship between noise exposure, health outcomes, and efficacy in public bus drivers: a structural equation modeling approach.

A comprehensive investigation was undertaken to evaluate the noise exposure levels received by public bus drivers and its potential consequences on their efficacy and health. Noise exposure levels were measured for drivers across forty distinct routes, followed by subjective data collection from 410 drivers through in-depth personal interviews. Noise exposure levels were quantified using time-weighted average sound pressure level (TWA) and noise dose, which were compared to Occupational Safety and Health Administration (OSHA) standards referred to as action level (85 dB and 50% noise dose) and criterion level (90 dB and 100% noise dose). The questionnaire responses were subjected to rigorous statistical analysis to delve deeper into the psychological effects of noise. Exploratory Factor Analysis (EFA) was employed to identify underlying factors, while structural equation modeling (SEM) was utilized to examine the relationships between these factors. The findings revealed that the TWA and noise dose surpassed the criterion and action level for drivers for eight and 25 routes, respectively. The SEM model, validated by robust goodness-of-fit indices such as chi-square (218.79), Chi-square minimum divided by degrees of freedom (2.166), normed fit index (0.904), and RMSEA (0.008), revealed that noise-related annoyance and speech intelligibility emerged as the primary factors adversely impacting drivers' efficacy and health. Secondary factors, including age, experience, and individual sensitivity to noise, were also found to play a significant role in modulating the impact of noise exposure. Finally, strategic policies were proposed to mitigate noise at its source and reduce its adverse effects on bus drivers.