Predicting Accident Probability from Frequency of Microsleep Events

There is growing acknowledgement that fatigue plays a significant role in traffic accidents. This study evaluated the relationship between fatigue-related accidents and Micro- Sleep Events (MSE) using a real car driving simulator. Ten healthy volunteers participated in the study for two nights each. After a period of struggling against sleep pressure, all subjects experienced periods of extreme fatigue and Micro-Sleep Events (MSE). Most MSE had no consequences, but some resulted directly in an accident. To establish a correlation between MSE and fatigue related accidents all MSE were counted separately for driving sessions with and without accidents. Accident probability was calculated as the ratio of the number of MSE in the accident sessions to the total number of MSE. Under the extremely fatiguing protocols the overall accident probability was 35%.