Abstract
A newly developed microcomputer- based drowsiness warning sys tem is described, which detects changes in the drivers's alertness through his steering behavior.In developing this system, first several levels of alertness based on such phy- siological factors as brain activity and blinking are quanti fied.Tests were then conducted in which drivers fell into different degrees of drowsiness.Using the quantified alert- ness levels the "drowsy driver" was defined and steering patterns were found, that could not be seen in normal driving