Every year thousands of adolescents require medical attention due to pedestrian injury. Many factors contribute to safe pedestrian behavior. Among them are reaction time, impulsivity, risk-taking, and attention. Sleep deprivation negatively influences these same characteristics that influence pedestrian safety. This study will investigate whether sleep restriction reduces adolescents' pedestrian safety. Subjects will engage in a virtual reality pedestrian environment in two conditions: a sleep deprived condition (4 hours sleep the previous night) and an adequate sleep condition (8 hours sleep the previous night). Adolescents may be riskier pedestrians when sleep deprived compared to when adequately rested. Risk will be displayed in a virtual pedestrian environment through increased numbers of close calls, hits, and missed safe opportunities, longer start delays, decreased gap sizes, and less attention to traffic.
The study will have broad implications in two areas. First, it will provide new knowledge to help inform policy decisions, such as school start times. Second, research demonstrating the increased pedestrian risk of sleep restricted adolescents might promote parental enforcement of earlier bedtimes on nights before adolescents will be walking somewhere (or, alternatively, encourage parents to drive their adolescents to school on mornings when they were unable to sleep an adequate amount). Each of these outcomes could ultimately result in fewer pedestrian injuries in adolescents. Overall, this study may raise awareness about the significance of adequate sleep in adolescents and promote healthier sleep habits.
Results showed that inadequate sleep influenced adolescents’ pedestrian behavior. When fatigued, adolescents took longer to initiate street-crossing, left less time between themselves and oncoming vehicles, experienced more hits/close calls with virtual vehicles, had fewer average missed safe opportunities to cross the street, and paid less attention to traffic before crossing in the virtual pedestrian environment. Stated numerically, adolescents who had inadequate sleep – who had slept less than 5 hours the night before – had over 50% more hits/close calls with virtual vehicles than when they were adequately rested. In fact, while sleep restricted, adolescents experienced a hit or close call on 2.22 of the 25 simulated crossings, or nearly 9% of the time. The generally riskier pedestrian behaviors among adolescents who had not received adequate sleep were likely caused by the cognitive effects of inadequate sleep. Safe pedestrian behavior requires attention to oncoming traffic, and we found that sleep-restricted adolescents were less attentive to traffic, as measured by their looks left and right while waiting to cross safely. Safe pedestrian behavior also requires impulse control; we found sleep-restricted adolescents made risky decisions by crossing in potentially dangerous traffic gaps. Finally, safe pedestrian behavior requires efficient, rapid, and precise decision-making; a pedestrian must perceive and judge the safety of a traffic gap very quickly and then initiate movement into it, and adolescents who were tired performed poorly at that task. Taken together, our results suggest acute inadequate sleep, and the cognitive effects associated with it, may have real-life implications for adolescents engaging in everyday activities such as crossing streets. These results are particularly concerning given evidence that acute inadequate sleep is common among American adolescents. The results have implications in at least three areas. First, our results confirm the benefit of pediatricians promoting sleep hygiene among adolescent patients. Well-patient visits typically involve counseling on preventative health topics, and such counseling effectively can instigate healthy behavior change. Sleep hygiene is often not included in such counseling, but given our results, the fact that unintentional injury is the leading cause of adolescent death in the US, and the other consequences of inadequate sleep, such as decreased school performance, it may be worthwhile for pediatricians to include sleep hygiene among topics addressed during preventative counseling discussions with adolescent patients and their parents. Second, this information could educate policy decisions about school start times. Previous research suggests inadequate sleep leads to decreased academic performance. Combined with our findings that inadequate sleep may also jeopardize pedestrian safety, policymakers might consider delaying middle and high school start times to provide safer travel to school and better academic performance once present. Finally, the results might influence parents to enforce appropriate bedtimes. Appropriate parental-set bedtimes are associated with lower depression and suicidal ideation in adolescents, and they may also reduce adolescents’ risk of pedestrian injury. These results may inform parents of the risk associated with losing only one night’s sleep.
