The nature of the risk faced by pedestrians with neurodevelopmental disorders: A systematic review.

Pedestrians represent one of the most vulnerable road user groups worldwide. Children and adult pedestrians with neurodevelopmental disorders may be at greater risk due to deficits in a range of domains, such as attention, social communication, motor control and executive function. According to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (American Psychological Association, 2013), neurodevelopmental disorders include individuals with a diagnosis of Autism Spectrum Disorders, Attention Deficit Hyperactivity Disorder, Specific Learning Disorder, Motor Difficulties, Communication Disorders and Intellectual Disabilities. The purpose of this systematic review and meta-analysis was to explore existing literature relating to determine the nature of the risk faced by pedestrians with neurodevelopmental disorders. Relevant databases including Web of Science, PhysInfo and CINAHL were searched up to July 2019. All peer reviewed journals that presented data focusing on neurodevelopmental disorders and some aspect of road crossing or roadside behaviour that included a control or comparison group were included. A total of 149 abstracts were assessed and 17 met the inclusion criteria. The identified papers could be grouped into four areas: (1) rate of injury; (2) assessment of risk; (3) eye gaze and understanding of road layout and (4) gap choice. No papers exploring the risk factors at the roadside for individuals with Specific Learning Disorders or Communication Disorders were identified. Overall, the review provide evidence for an elevated risk of injury for individuals with ADHD at the roadside, potentially as a consequence of poor temporal gap choice, although there was evidence that this risk could be mediated by executive dysfunction rather than ADHD symptomology. Furthermore, poor temporal gap choice was found in children with DCD but it remains unclear as to whether this risk translates to the roadside. Finally, both children and adults with ASD and children with ID were found to demonstrate differences in behaviour / understanding at the roadside. In general, co-occurrence between neurodevelopmental disorders has been largely ignored in the current literature relating to pedestrian risk and future research could consider this along with executive functioning.