Monash University Accident Research Centre (MUARC) was approached by Sleep Diagnostics to conduct an evaluation of the Optalert system in terms of its effectiveness in predicting a breakdown in driving performance, using the MUARC advanced driving simulator. The aim of the current study was to determine whether there is a breakdown in driving performance during the period after which the Johns Drowsiness Scale (JDS) reaches the cautionary level (4.5) and the critical level (5.0), that is, after the driver is classified as drowsy by the Optalert system. Based upon previous research using the Optalert system, Sleep Diagnostics defined the period of interest to be 30 minutes after the JDS reached the cautionary or critical levels. The analyses were also repeated for shorter periods, of 15 minutes and 5 minutes after the participant reached the cautionary or critical JDS level. It is important to note that the Optalert system is designed to predict drowsiness well ahead of when a warning would be given, and so, the longer time intervals of 15 minutes and 30 minutes are of greater interest in this study. (Author/publisher)
Samenvatting