Psychophysiological characteristics of driver fatigue

Driver fatigue is known to be a major risk factor for road and work-related accidents that can often result in serious injury or death. However, despite the obvious need to investigate factors that may contribute to this problem, there still remains considerable uncertainty and debate concerning determinants of driver related fatigue. In other words, factors that contribute to a person fatiguing when they perform a sensor-motor task like driving a motor vehicle over an extended period of time. This chapter discusses definitions of driver fatigue, possible symptoms, and the contribution of psychophysiological factors. The chapter will also present findings from a driver simulator study that investigated both physiological and psychological determinants of fatigue. It involved three outcome measures, including a physiological, psychological and a combined physiological and psychological measure. Participants included 50 male and female adults who held a current drivers license. All subjects performed a driving simulator task till they exhibited symptoms of fatigue in a temperature controlled laboratory. They were assessed immediately before and after the simulated driving task, as well as throughout the driving task, using a comprehensive assessment regimen including general health, brain wave activity, heart rate variability, respiration, eye blink activity, peripheral skin temperature, and psychological measures of personality, fatigue and mood states. Significant predictors for the physiological fatigue measure included higher levels of delta activity and low levels of liveliness and self-sufficiency. Determinants for the psychological fatigue outcome measure included anxiety, low levels of vigor and low levels of self-sufficiency. The combined fatigue outcome measure was determined by factors such as anxiety, low levels of self-sufficiency and high levels of theta activity. These results are believed to support a two-level processing model of fatigue. The findings underline the importance of assessing fatigue using a range of outcome measures in order to understand what factors contribute to driver related fatigue and highlight the need to develop fatigue countermeasures that employ a broad range of measures. © 2011 by Nova Science Publishers, Inc. All rights reserved