Iranian Journal of Ergonomics

Introduction: Driver fatigue is one of the major causes of accidents in roads. It is suggested that driver fatigue and drowsiness accounted for more than 30% of road accidents. Therefore, it is important to use features for real-time detection of driver mental fatigue to minimize transportation fatalities. The purpose of this study was to explore the EEG alpha power variations in sleep deprived drivers on a car driving simulator.

Materials and Methods: The present descriptive-analytical study was achieved on nineteen healthy male car drivers. After taking informed written consent, the subjects were requested to stay awake 18 hrs before the experiments and refrain from caffeinated drinks or any other stimulant as well as cigarette smoking for 12 hrs prior to the experiments. The drivers sleep patterns were studied through sleep diary for one week before the experiment. The participants performed a simulated driving task in a 110 Km monotonous route at the fixed speed of 90 km/hr. The subjective self-assessment of fatigue was performed in every 10 minute interval during the driving using Karolinska Sleepiness Scale (KSS). At the same time, video recordings from the drivers face and their behaviors were achieved in lateral and front views and rated by two trained observers. Continuous EEG and EOG records were taken with 16 channels during driving. After filtering and artifact removal, power spectrum density and fast Fourier transform (FFT) were used to determine the absolute and relative alpha powers in the initial and final 10 minutes of driving. To analyze the data, descriptive statistics, Pearson and Spearman coefficients and paired-sample T test were employed to describe and compare the variables.

Results: The findings showed a significant increase in KSS scores in the final 10 minutes of driving (p<0.001). Similar results were obtained concerning video rating scores. Meanwhile, there was a significant increase in the absolute alpha power during the final section of driving (p=0.006).

Conclusion: Driver mental fatigue is considered as one of the major implications for road safety. This study suggests that alpha brain wave rhythm can be a good indicator for early prediction of driver fatigue.

Introduction: One of the most important subjects in the analysis of driver’s behavior had been situation awareness during the past decade. However, no study has been investigated the relation among component of situation awareness and performance and cognitive abilities of bus drivers. Current study aimed to survey relationship between bus drivers’ situation awareness, driving performance and cognitive abilities using driving simulator.

Material and Methods: In this study, 30 professional bus drivers who have diploma or higher degree participated. Situation awareness measured by SAGAT technique and tests UFOV, EFT and WMS were used for measuring of cognitive abilities. Brake reaction time and lane departures were criteria for driving performance.

Results: Accordingly, the result showed significant relation between drivers’ situation awareness before and after hazard conditions. Among WMS, divided attention, selective attention and EFT with level 1 of situation awareness was seen significant relation. The result of current study released a significant correlation among WMS and divided attention with lane departure.

Conclusion: Results showed, in general, the driver's situational awareness in dangerous conditions increases. The study showed that cognitive ability affects only level 1 of situational awareness. According to role of situational awareness in driving performance, the results of lane keeping showed that perception might be a key factor in driving performance.