Detecting drowsiness while driving by measuring eye movement - a pilot study

A function to warn a drowsy driver is a prospective device to be included in intelligent transportation systems. We compared the eye closure rate (PERCLOS) with the vertical eye movement frequency between wakeful and drowsy states of drivers who were driving a car in a driving simulator. Three subjects participated in the experiment. In the drowsy state condition, both measures showed high values in frequency, which was significant enough to distinguish between the two states with a threshold. The threshold level, which can distinguish the two states, is defined as the rate at the cross point of the curves of two possibility density functions made by the frequency of the rates of the two measures at the two states. The distinction error was evaluated for three analysis durations. As a result of the analysis, it was found that the better measure was different for each subject.