Study Objectives: Many cognitive factors contribute to unintentional pedestrian injury, including reaction time, impulsivity, risk-taking, attention, and decision-making. These same factors are negatively influenced by excessive daytime sleepiness (EDS), which may place children with EDS at greater risk for pedestrian injury. Design, Participants, and Methods: Using a case-control design, 33 children age 8 to 16 y with EDS from an established diagnosis of narcolepsy or idiopathic hypersomnia (IHS) engaged in a virtual reality pedestrian environment while unmedicated. Thirty-three healthy children matched by age, race, sex, and household income served as controls. Results: Children with EDS were riskier pedestrians than healthy children. They were twice as likely to be struck by a virtual vehicle in the virtual pedestrian environment than healthy controls. Attentional skills of looking at oncoming traffic were not impaired among children with EDS, but decision-making for when to cross the street safely was significantly impaired. Conclusions: Results suggest excessive daytime sleepiness (EDS) from the clinical sleep disorders known as the hypersomnias of central origin may have significant consequences on children's daytime functioning in a critical domain of personal safety, pedestrian skills. Cognitive processes involved in safe pedestrian crossings may be impaired in children with EDS. In the pedestrian simulation, children with EDS appeared to show a pattern consistent with inattentional blindness, in that they "looked but did not process" information in their pedestrian environment. Results highlight the need for heightened awareness of potentially irreversible consequences of untreated sleep disorders and identify a possible target for pediatric injury prevention.