Background and aims : Among all systems that each person may interact with in daily life public transportation systems may expose them to various risks. The noise exposure of drivers can cause accidents through developing hearing loss and stress and consequent impact on driver’s safety performance. The main objective of this study was to evaluate the relation between noise exposure and occupational stress with unsafe acts and car accidents among city-bus drivers of Hamadan.

  Methods : This cross-sectional study was conducted in spring of 2011 . Fifty four drivers were chosen using simple random sampling among Hamadan city bus drivers. The required data gathering was done by using sound level meter, job stress questionnaire, personal characteristics questionnaire, safety behavior sampling technique and checklist of accidents. Data analysis was done with statistical tests including t-test, logistic regression and one-way ANOVA.

  Results: The obtained results indicated that 76% of drivers were at the high stress level, the percentage of unsafe acts among them was 42.71% and their noise exposure was at high risk levels. In addition, our results showed that the probability of accidents and unsafe acts was increased with the increasing of noise exposure and job stress.

  Conclusion: Because of high stress level, high percent of unsafe acts and noise exposure in studied drivers, they are vulnerable to accident. Thus decreasing the stress level and unsafe acts through implementation of a comprehensive stress management program and education of drivers about following safety is required.

  Keywords: noise exposure, job stress, unsafe acts, traffic accidents