ارزیابی ذهنی و عینی بار کار فکری اپراتورها در یک مرکز کنترل ترافیک شهری

 Background and aims: Modern technology has imposed more cognitive demands than physical demands to operators in most workplaces.The Increase of cognitive demands in real working conditions can have negative effect on the mental health and performance of operators. This study was coducted with the aim of subjective and objective evaluation of operators’ mental workload in a city traffic control room.  Methods: In this study 16 opeartors of a traffic control center participated voluntarily. In setteled day at resting condition the physiological indices were measured for 5 minutes before the work started and after it was finished for each operator. Regarding to the city traffic density (low and high mental work conditions) the physiological indices were measured for 5 minuts in each condition. Also at the end of each condition the NASA-TLX questionaire was completed by each operator. The data were analysed using t-test and repaeated measure analysis of variance by SPSS.21 software. Results: The Results of our paired t-test showed a significant differences between the subjective responses of operators in all dimensions of NASA-TLX except for physical demand in low mental workload condition compared to high mental workload.The Findings of the repeated measures of ANOVA showed that there is a significant differences between the mean of heart rate, SDNN, RMSSD  and LF/HF ratio features by increasing difficulty of mental work compared to before and after rests among operators. Conclusion: Our finding indicated that with increasing traffic density a lot of mental load imposed to operators that can cause to mental health problem and decrease performance among operators in future. Therfore, in the traffic control room, organizing and managing human resources based on the work load of the work in different working conditions is recommended.