Psychophysiological Changes Associated With Self-Regulation of Sleepiness and Cessation From a Hazard Perception Task

Abstract

Abstract. The relationship between a driver’s ability to identify increasing sleepiness and ceasing driving when sleepy is relatively unexamined. Several studies suggest that drivers have some ability to identify increasing levels of sleepiness. However, whether that identification of sleepiness leads to drivers being able to self-regulate and cease driving has not been examined. This study assessed the capacity of drivers to identify sleepiness and to self-regulate their own simulated driving cessation. Twenty-six young adults completed a validated hazard perception simulated task when moderately sleep deprived after a 05:00 wakeup. Participants were instructed to stop driving if they thought they were too sleepy to drive safely on the road. Physiological (EEG, EOG, and ECG) and subjective (Karolinska Sleepiness scale) measures were used to examine self-regulation of simulated driving cessation. The behavioral validity of the participants’ subjective sleepiness was then examined with a 30 min nap opportunity. All participants ceased the task on average after approximately 40 min (range = 12.5–73 min). No participant was judged to have experienced any microsleeps or fallen asleep. Subjective sleepiness and EOG-based blink duration measures increased significantly from the beginning of the drive to the end of the simulated driving episodes. During the nap opportunity 23 of the 26 participants were able to achieve sleep onset. The results suggest that moderately sleep deprived individuals can identify increasing sleepiness and then take action to cease a hazard perception task. Potentially, on-road drivers could benefit from better elicitation of subjective sleepiness and their self-regulation of driving cessation.