Research on Heart Rate and Eye Movement as Indicators of Drivers’ Mental Workload

In this research, 16 of 24 car drivers, including 8 experienced and 8 novice drivers, were recruited as participants. In the tests, when diving on an urban road, the participants’ heart rates were recorded by use of a KF2 physiological monitor, and eye movement data were collected by use of an EyeLink Ⅱ eye movement tracking device. The test road was divided into 27 segments, including non-intersection roads (divided by central reservation, barrier or central line), intersections, and overpass / underpass interchanges. Taking the fluctuating rate of heart rates, the square root mean square of the difference between successive rhythm-to-rhythm (RR) intervals (RMSSD), and low frequency (LF) as indicators of a driver’s mental workload, the influences of road section types and driving experience upon drivers’ mental workload were analyzed, and the correlation between drivers’ eye movement and electrocardio indicators was explored. The research results indicate that drivers’ mental workload is affected by road section types and driving experience. When driving on the same road, the mental stress upon the experienced driver group is lower than that of the novice driver group. By analyzing the correlation between eye movement and heart rate, it is found that a driver’s mental workload has much more influence on the saccade behavior than on fixation (gaze) behavior.