Driving without awareness: Examination of the phenomenon

In studies concerning driver state, particularly attention loss and driver drowsiness, a phenomenon can be observed which we refer to as driving without awareness (DWA). The purpose of the study presented here is to learn more about the underlying characteristics of this symptom of driver drowsiness that occurs if the will to keep one’s eyes open overrides the physiolo gical need of a drowsy person to close his or her eyes. The crucial part of the presented analysis is the examination of the connection of DWA and micro sleep, the risk factors for DWA and a comparison of blink parameters. Experimental series in a driving simulator have revealed that almost every fifth driver shows states of deep unawareness during a monotonous drive on a simulated highway. The states of DWA occur predominantly together with events of so-called micro sleep. To confirm this finding, a follow-up study with 38 test-drivers has been analyzed in which subjects appeared twice to the test, under different test conditions concerning daytime. Subsequently, the method of video analysis was applied to document acute states of DWA and of micro sleep events. Results show that DWA often precedes or accompanies micro sleep. The occurrence of DWA seems to come along with certain patterns in blink behaviour, which are more similar to micro sleep events than to a state of being awake. These findings support our assumption that DWA is a precursor of falling asleep.