Sleepiness and nocturnal driving safety: a study on risk perception in young drivers

Introduction: It is well known that young drivers are a population at risk for nocturnal car accidents related to sleepiness. Several authors suggested that young novice drivers are characterized by perceiving relatively low levels of risk in specific driving situations compared to other groups of drivers. Nevertheless, there is a lack of studies directly aimed at evaluating how young drivers perceive the risk of sleepy driving, and to examine factors associated to this perception. The present study is aimed to evaluate: (1) the factors that affect the risk perception related to nocturnal driving in young people; (2) whether, according to the Prospect Theory, the way of presenting information influences evaluations and choices regarding night time driving. Method: Six hundred and ninety five young drivers (57.6% females and 42.4% males; mean age 20.85 years) answered to questions regarding different aspects of night time driving. All subjects answered to questions on risk perception of sleep related accidents, on nocturnal driving experience and on strategies adopted to counterattack sleepiness. Furthermore, subjects analysed three different decision making problems regarding nocturnal driving. They would request (a) to evaluate the risk to drive in a particular condition of sleepiness; (b) to rate how much they would comply themselves with preventive behaviors; (c) to choose between two alternative preventive strategies (one described in terms of sure but little effects, the other in terms of uncertain but great effects) to reduce the likelihood of having a nocturnal car accident due to somnolence. Half of the subjects answered to the three problems that were presented in a positive frame (e.g. emphasizing the positive consequences of the adoption of a behavior) while other half answered to the three problems that were formulated in a negative frame (e.g. emphasizing the negative consequences of not adopting the same behavior). Results: Results show that experiences of sleep attacks during driving and nocturnal driving frequency are factors that affect both the risk perception [F(1,680) = 16.8; P = 0.001] and the commitment in adopting preventive strategies (Wald(1) = 21.4; P < 0.001). Furthermore, the manipulation of informative framing significantly affects subjective evaluations [F(1,673) = 3.29; P < 0.001] and risk choices (Chi2 (1) = 9.1; P < 0.01). Discussion: Results confirm that small changes in wording a decision problem affect evaluation and choices of responders regarding nighttime driving. Results provide suggestions about the way to present information in educational programs against sleep related vehicle accidents among young drivers.