The potentially harmful effects of sleep deprivation and circadian troughs are well documented within fatigue and transportation research. However, less attention has been paid to the role of personality and motivational factors in decision-making about the onset and progression of fatigue. Recent research has indicated that taxi drivers who report falling asleep at the wheel have significantly higher rates of general risk-taking while driving. The current study sought to replicate this finding with a broader range of subjects. One hundred and thirteen university students and seventy parents of the student group completed a survey about attitudes to driving. The survey examined the relationship between risk-taking while driving and falling sleep at the wheel, as well as optimism bias, social desirability, and driving-related variables. Analysis indicated that drivers who had fallen asleep at the wheel had significantly higher risk-taking scores, even when confounding variables such as social desirability and percentage of night driving were taken into account. Correlations between individual scale items provided additional information concerning attitudes to fatigue, including a finding of pessimistic (rather than optimistic) relative judgements towards driving safely when very tired. The findings of this study are discussed within the context of a more general theory of fatigue which allows for the impairment of metacognitive fatigue detection systems as cellular fatigue progresses. Individual differences in dealing with the early stages of fatigue are suggested as a reason for differences in rates of falling asleep at the wheel. (A)
Abstract