The paper investigates parameters derived from eyelids movements reflecting drivers impairment at the wheel, and assesses correlation between impairment and the newly established eye closure indicators. On the one hand, distributions of eye closure rates show a similar mathematical shape, while on the other hand their calculated threshold values fluctuate between 10% and 100%, confirming the onset of the transitional periods of impairment during the drive. Results confirm the appearance of large shape of distributions of eyes closing corresponding to impairment. These measures show that 30% to 40% of the time of the driving periods, subjects fluctuated from transitional to impaired states. Differences between the average rate of eyes closing in each hourly period have been observed. It was also observed that these differences are strongly dependent on each subject and varies between -8% and +12%.
Abstract