Roadside experiences of parents of children with developmental coordination disorder and/or attention deficit hyperactivity disorder.

Introduction: Pedestrians are a vulnerable group at the roadside and previous research has identified that children with DCD and ADHD are at a heightened risk of pedestrian injuries. Despite this, limited research has explored parental perspectives of the pedestrian risks faced by children with DCD and/or ADHD. Understanding parents' perspectives provides a unique insight into the challenges children face every day and the concerns that parents perceive regarding their children's safety as pedestrians. Therefore, the aim of this study was to explore parents' perspectives of the pedestrian risks faced by their children with DCD and/or ADHD. Methods: Semi-structured interviews were conducted with 14 parents of primary school and early secondary school aged children with age range 7-17. The participants were divided into three groups based on their children's conditions: DCD group (10-17 years, n = 3), ADHD group (7-13 years, n = 5), and co-occurring group (7-16 years, n = 6). All parents confirmed an existing diagnosis and completed the SNAP-IV and DCDQ as screening tools. The interviews explored parents' perspectives regarding their children's pedestrian behaviors, parents' concerns and preventative measures taken to improve the pedestrian safety of their children with DCD and/or ADHD. Reflexive thematic analysis was undertaken to analyze the interviews, from which three themes were developed. Results: The first theme related to the challenges experienced by children at the roadside; parents emphasized the significance of structured and controlled pedestrian crossing sites, underlining their preference for designated crossings as safer options due to their heightened perceptions of risk associated with other road-crossing locations. The second theme: parental concerns and influences on children's road safety referred to their children's performance and safety at the roadside, leading to increased monitoring and a more protective approach to road crossing. The third theme: road safety education related to various strategies parents implemented to mitigate risks, while balancing independence and prioritizing their safety. Discussion: While there were commonalities in the challenges faced by children with DCD and/or ADHD at the roadside, there were also notable differences. Parents of children with DCD discussed challenges with spatial awareness and motor skills, whereas parents of children with ADHD discussed challenges with impulsivity and inattention. Parents of children with co-occurring DCD and ADHD described a complex interplay of these challenges. It is evident from the interviews that children with DCD and/or ADHD require a distinct approach to develop their pedestrian skills effectively and parents reported specific strategies they used to address the risks associated with their children's roadside behavior. Promoting pedestrian safety for children with DCD and/or ADHD necessitates collaboration among parents, schools and local authorities to implement comprehensive measures ensuring their safety. These findings contribute to understanding parental experiences and needs, providing valuable guidance for targeted interventions and policies to enhance the road safety of children with DCD and/or ADHD.

Exploring the presence and impact of sensory differences in children with Developmental Coordination Disorder.

BACKGROUND: Children with Developmental Coordination Disorder (DCD) can experience sensory differences. There has been limited exploration of these differences and their impact on children with DCD. AIMS: i) To explore the presence and impact of sensory differences in children with DCD compared to children without DCD; ii) To examine whether sensory differences are related to motor ability, attention deficit hyperactivity disorder (ADHD), or autistic traits. METHOD: Parents of children (8-12 years) with (n = 23) and without (n = 33) DCD used standardised questionnaires to report on their children's sensory differences, autistic traits, and ADHD traits. Motor abilities were assessed through the Movement Assessment Battery for Children-2. Data were explored both categorically (between-groups) and dimensionally. RESULTS: Children with DCD had significantly higher levels of sensory differences than children without DCD. Sensory differences also had a significantly greater impact on daily activities for children with DCD. Higher levels of ADHD and autistic traits, but not motor ability, were significant independent predictors of higher levels of sensory difference. CONCLUSION: Children with DCD experience high levels of sensory differences, which impact on their daily lives. These sensory differences may be a marker for additional neurodivergence in children with DCD. Practitioners should consider the sensory needs of children with DCD. WHAT THIS PAPER ADDS: This paper provides insight into the sensory features of children with DCD and the impact that sensory differences can have on daily living. Using parent-report, we found that children with DCD had increased sensory differences relative to children without DCD. These included increased hyperresponsiveness, increased hyporesponsiveness, and increased sensory interests, repetitions, and seeking behaviours (SIRS). We also found that sensory differences had a greater impact on daily living for children with DCD compared to children without DCD. Across the whole sample, autistic traits predicted hyperresponsivity and hyporesponsivity patterns; whereas traits of hyperactivity and impulsivity predicted SIRS. Motor abilities did not uniquely predict sensory differences, suggesting that other traits of neurodivergence may contribute to the sensory differences in DCD. Taken together, these findings highlight the necessity of considering sensory needs when supporting children with DCD. They also suggest that if sensory differences are identified in children with DCD, it may be due to the presence of co-occurring neurodivergent traits or conditions.

Spirochaete genome identified in red abalone sample represents a novel genus Candidatus Haliotispira gen. nov. within the order Spirochaetales.

A fully assembled spirochaete genome was identified as a contaminating scaffold in our red abalone (Haliotis rufescens) genome assembly. In this paper, we describe the analysis of this bacterial genome. The assembled spirochaete genome is 3.25 Mb in size with 48.5 mol% G+C content. The proteomes of 38 species were compared with the spirochaete genome and it was discovered to form an independent branch within the family Spirochaetaceae on the phylogenetic tree. The comparison of 16S rRNA sequences and average nucleotide identity scores between the spirochaete genome with known species of different families in Spirochaetia indicate that it is an unknown species. Further, the percentage of conserved proteins compared to neighbouring taxa confirm that it does not belong to a known genus within Spirochaetaceae. We propose the name Candidatus Haliotispira prima gen. nov., sp. nov. based on its taxonomic placement and origin. We also tested for the presence of this species in different species of abalone and found that it is also present in white abalone (Haliotis sorenseni). In addition, we highlight the need for better classification of taxa within the class Spirochaetia.

Understanding factors that influence physical activity behavior in people with developmental coordination disorder (DCD): a mixed-methods convergent integrated systematic review.

This systematic review synthesizes the literature on physical activity amongst people with DCD using the COM-B framework. The review questions were: (1) what is the Capability (C), Opportunity (O) and Motivation (M) for physical activity and (2) what does physical activity behavior (B) look like? A mixed-methods systematic review was conducted by searching eight databases (PubMed, APA PsycINFO, EMBASE, Scopus, Child Development and Adolescent Studies, Cochrane Library, Web of Science, CINAHL) up to July 2023. Data were extracted, thematically analyzed, and mapped to the COM-B model. The quality of studies was assessed with the Joanna Briggs Institute (JBI) critical appraisal tool. The protocol was registered with PROSPERO (CRD42022319127). Forty-three papers, 42 of which related to children, were included. Fifteen aligned with physical activity behavior, nine with physical capability, thirteen with psychological capability, one with social opportunity, one with physical opportunity, one with reflective motivation and three with automatic motivation. Pre-school-aged children with DCD engage in comparable levels of physical activity behavior, but differences emerge from 6 years of age. Characteristics of DCD result in reduced physical capability and less varied participation in physical activity. This impacts psychological capability, whereby lower self-perceptions result in a negative feedback loop and reduce the motivation to participate. Barriers relating to social opportunities may result in poor reflective and automatic motivation, although there is evidence that interventions can enhance enjoyment in the short term.

Possible disrupted biological movement processing in Developmental Coordination Disorder.

AIM: There is emerging evidence that the Mirror Neuron System (MNS) might contribute to the motor learning difficulties characteristic of Developmental Coordination Disorder (DCD). This study aimed to identify whether MNS activity differed between children with and without DCD during action observation, action execution and during a non-action baseline. METHODS: Electroencephalography (EEG) was used to measure mu rhythm (a proxy for MNS activation) in 8-12-year-old children either with (n = 20) or without (n = 19) a diagnosis of DCD. The mu rhythm was recorded at rest and during five experimental conditions: (1) observation of gross motor and (2) fine motor actions; (3) execution of gross motor and (4) fine motor actions; and (5) non-biological movement. To address whether potential co-occurring traits of other neurodevelopmental conditions were associated with differences in mu rhythm, parents reported their child's attention and social communication skills. Mixed and repeated measure ANOVAs were conducted to examine differences in mu desynchronization and mu power respectively. RESULTS: The non-DCD group showed greater mu rhythm desynchronization than children with DCD (i.e., more MNS activity), with both groups demonstrating increasing desynchronization from observation of fine actions to execution of gross actions. However, we also found that the children with DCD had less mu power during the non-biological movement condition than the non-DCD children, although mu power did not differ between groups during the resting condition. Correlations between mu desynchronization and children's attention and motor skills showed that poorer attention and motor abilities were associated with reduced MNS activity. CONCLUSION: Compared to children without DCD, the MNS in children with DCD did not distinguish between biological and non-biological movement. It is possible that the reduced specificity of the MNS in children with DCD is an underlying factor in the motor impairments observed in the disorder. The differential MNS activity could reflect broader atypical activity in perceptual networks that feed into the MNS in DCD.

A mixed methods systematic review of digital interventions to support the psychological health and well-being of people living with dermatological conditions.

Background: Dermatological conditions can have a substantial impact on psychological as well as physical health yet dedicated face-to-face psychological support for patients is lacking. Thus, individuals may require additional support to self-manage dermatological conditions effectively. Digital technology can contribute to long-term condition management, but knowledge of the effectiveness of digital interventions addressing psychological (cognitive, emotional, and behavioural) aspects of dermatological conditions is limited. Objectives: To identify, determine the effectiveness, and explore people's views and experiences of digital interventions supporting the psychological health of people with dermatological conditions. Methods: A mixed methods systematic review informed by JBI methodology. The protocol was registered on PROSPERO. Eight electronic databases were searched for papers written between January 2002 and October 2021. Data screening and extraction were conducted in Covidence. The methodological quality of studies were scrutinised against JBI critical appraisal tools. Intervention characteristics were captured using the Template for Intervention Description and Replication checklist and guide. Data were synthesised using a convergent segregated approach. The results were reported in a narrative summary. Results: Twenty-three papers were identified from 4,883 references, including 15 randomised controlled trials. Nineteen interventions were condition-specific, 13 were delivered online, 16 involved an educational component, and 7 endorsed established, evidence-based therapeutic approaches. Improvements in knowledge, mood, quality of life, the therapeutic relationship, and reduced disease severity in the short to medium term, were reported, although there was substantial heterogeneity within the literature. Thirteen studies captured feedback from users, who considered various digital interventions as convenient and helpful for improving knowledge, emotion regulation, and personal control, but technical and individual barriers to use were reported. Use of established qualitative methodologies was limited and, in some cases, poorly reported. Conclusion: Some web-based digital psychological interventions seem to be acceptable to people living with mainly psoriasis and eczema. Whilst some digital interventions benefitted cognitive and emotional factors, heterogeneity and inconsistencies in the literature meant definitive statements about their effectiveness could not be drawn. Interdisciplinary and patient-centred approaches to research are needed to develop and test quality digital interventions supporting the psychological health of adults living with common and rare dermatological conditions. Systematic review registration: [https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=285435], identifier [CRD42021285435].

Why Are Older Adults More at Risk as Pedestrians? A Systematic Review.

OBJECTIVE: To explore factors that could explain why older adults are more at risk at the roadside. BACKGROUND: The physical and psychological health benefits of walking have been well-established, leading to the widespread promotion of walking amongst older adults. However, walking can result in an increased risk of injury as a pedestrian at the roadside, which is a greater risk for older adults who are overrepresented in pedestrian casualty figures. METHOD: Relevant databases were searched up to January 2020. All peer-reviewed journals that presented data on healthy older adults and some aspect of road crossing or roadside behavior were included. A total of 142 papers were assessed and 60 met the inclusion criteria. RESULTS: Identified papers could be grouped into three areas: crossing at a designated crossing place; crossing with no designated crossing place; perceptions or behaviors. CONCLUSION: Multiple individual (attitudes, perceived behavioral control, walking time, time-to-arrival judgments, waiting endurance, cognitive ability), task (vehicle size, vehicle speed, traffic volume), and environmental (road layout, time of day, weather) constraints influence road crossing in older adulthood. APPLICATION: Accessibility of designated crossing areas needs to be addressed by ensuring sufficient time to cross and nonrestrictive waiting times. Signalized crossings need to be simplified and visibility increased. Where there is no designated crossing place, a reduction in speed limit alongside the provision of pedestrian islands to provide "pause" places are needed. Educational-based programs may also help ensure safety of older adults where there is no designated crossing place.

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.

The Lived Experience of Crossing the Road When You Have Developmental Coordination Disorder (DCD): The Perspectives of Parents of Children With DCD and Adults With DCD.

Pedestrians are one of the most vulnerable groups at the roadside, furthermore, previous research has demonstrated perceptual-motor limitations in individuals with DCD which may put these individuals at even more at risk in the context of road crossing. However, it is unclear whether this is the lived experience of these individuals at the roadside. Furthermore, difficulties with road crossing and safety have been found in other neurodevelopmental disorders but the impact this might have on an individual with co-occurring difficulties is unknown. Therefore, we utilized a questionnaire to survey the lived experience of adults with DCD and parents of children with DCD with the specific objectives of describing behaviors exhibited by adults and children with DCD (the latter reported by parents) at the roadside and to determine the how these individuals perceive road crossing actions. For each of these we compared different co-occurrence groups. We also had one final objective which was not focused on road crossing but more on the general perception of accidents and unrealistic optimism. Individuals with co-occurrences which have previously been linked to unsafe crossing behaviors (i.e., ADHD, ASD, and LD) reported a greater regularity of dangerous looking behavior (forgetting to look, running without looking) and visibility (crossing between cars, crossing when you can't see), these adults and the parents of these children were seemingly aware of the risky nature of these behaviors. When asked "why" crossing ability might be different, perceptual and motor difficulties alongside heightened awareness of risk and lowered awareness of risk were all cited by participants. Unrealistic optimism was not an explanation for the risky behavior in adults with DCD and in fact, these adults demonstrated a clear understanding of the likelihood of accidents. The findings of this study suggest that road crossing is perceived to be more challenging for both children and adults with DCD and this needs to be taken into account when considering remediation for this group.

Genome to Phenome: Improving Animal Health, Production, and Well-Being - A New USDA Blueprint for Animal Genome Research 2018-2027.

In 2008, a consortium led by the Agricultural Research Service (ARS) and the National Institute for Food and Agriculture (NIFA) published the "Blueprint for USDA Efforts in Agricultural Animal Genomics 2008-2017," which served as a guiding document for research and funding in animal genomics. In the decade that followed, many of the goals set forth in the blueprint were accomplished. However, several other goals require further research. In addition, new topics not covered in the original blueprint, which are the result of emerging technologies, require exploration. To develop a new, updated blueprint, ARS and NIFA, along with scientists in the animal genomics field, convened a workshop titled "Genome to Phenome: A USDA Blueprint for Improving Animal Production" in November 2017, and these discussions were used to develop new goals for the next decade. Like the previous blueprint, these goals are grouped into the broad categories "Science to Practice," "Discovery Science," and "Infrastructure." New goals for characterizing the microbiome, enhancing the use of gene editing and other biotechnologies, and preserving genetic diversity are included in the new blueprint, along with updated goals within many genome research topics described in the previous blueprint. The updated blueprint that follows describes the vision, current state of the art, the research needed to advance the field, expected deliverables, and partnerships needed for each animal genomics research topic. Accomplishment of the goals described in the blueprint will significantly increase the ability to meet the demands for animal products by an increasing world population within the next decade.

An Annotated Genome for Haliotis rufescens (Red Abalone) and Resequenced Green, Pink, Pinto, Black, and White Abalone Species.

Abalone are one of the few marine taxa where aquaculture production dominates the global market as a result of increasing demand and declining natural stocks from overexploitation and disease. To better understand abalone biology, aid in conservation efforts for endangered abalone species, and gain insight into sustainable aquaculture, we created a draft genome of the red abalone (Haliotis rufescens). The approach to this genome draft included initial assembly using raw Illumina and PacBio sequencing data with MaSuRCA, before scaffolding using sequencing data generated from Chicago library preparations with HiRise2. This assembly approach resulted in 8,371 scaffolds and total length of 1.498 Gb; the N50 was 1.895 Mb, and the longest scaffold was 13.2 Mb. Gene models were predicted, using MAKER2, from RNA-Seq data and all related expressed sequence tags and proteins from NCBI; this resulted in 57,785 genes with an average length of 8,255 bp. In addition, single nucleotide polymorphisms were called on Illumina short-sequencing reads from five other eastern Pacific abalone species: the green (H. fulgens), pink (H. corrugata), pinto (H. kamtschatkana), black (H. cracherodii), and white (H. sorenseni) abalone. Phylogenetic relationships largely follow patterns detected by previous studies based on 1,784,991 high-quality single nucleotide polymorphisms. Among the six abalone species examined, the endangered white abalone appears to harbor the lowest levels of heterozygosity. This draft genome assembly and the sequencing data provide a foundation for genome-enabled aquaculture improvement for red abalone, and for genome-guided conservation efforts for the other five species and, in particular, for the endangered white and black abalone.

Understanding the Functional Mobility of Adults with Developmental Coordination Disorder (DCD) Through the International Classification of Functioning (ICF).

PURPOSE OF REVIEW: This phenomenological study explored the lived experience of six adults with developmental coordination disorder (DCD) and its potential impact on functional mobility. Utilising the International Classification of Functioning (World Health Organisation, 2001), the data derived from interviews were analysed to consider how persistent motor impairments impact on activity engagement and participation. RECENT FINDINGS: Much of the research evidence pertaining to DCD focuses on children. However, there is increasing acknowledgment that for some, the motor impairments synonymous with DCD continue into adulthood. SUMMARY: The findings from this study suggest that for this group of participants, functional mobility can be compromised, restricting activity and participation. At a body structure/function level, participants identified additional impairments that moved beyond mobility, suggesting that the secondary consequences of fatigue and anxiety were disabling. However, personal factors were seen to mitigate some difficulties encountered to allow participants to remain actively engaged in a range of adult roles.

Insights into teleost sex determination from the Seriola dorsalis genome assembly.

BACKGROUND: The assembly and annotation of a genome is a valuable resource for a species, with applications ranging from conservation genomics to gene discovery. Genomic resource development is especially important for species in culture, such as the California Yellowtail (Seriola dorsalis), the likely candidate for the establishment of commercial offshore aquaculture production in southern California. Genomic resource development for this species will improve the understanding of sex and other phenotypic traits, and allow for rapid increases in genetic improvement for and economic gain in culture production. RESULTS: We describe the assembly and annotation of the S. dorsalis genome, and present resequencing data from 45 male and 45 female wild-caught S. dorsalis used to identify a sex-determining region and marker in this species. The genome assembly captured approximately 93% of the total 685 MB genome with an average coverage depth of 180×. Using the assembled genome, resequencing data from the 90 fish were aligned to place boundaries on the sex-determining region. Sex-specific markers were developed based on a female-specific, 61 nucleotide deletion identified in that region. We hypothesize that Estradiol 17-beta-dehydrogenase is the putative sex-determining gene and propose a plausible genetic mechanism for ZW sex determination in S. dorsalis involving a female-specific deletion of a transcription factor binding motif that may be targeted by Sox3. CONCLUSIONS: Understanding the mechanism of sex determination and development of assays to determine sex is critical both for management of wild fisheries and for development of efficient and sustainable aquaculture practices. In addition, this genome assembly for S. dorsalis will be a substantial resource for a variety of future research applications.

The use of visually guided behaviour in children with Developmental Coordination Disorder (DCD) when crossing a virtual road.

The ability to safely cross a road is a perceptual-motor skill that involves coordination between a pedestrian's perception of the approaching vehicles and their locomotive capability to execute the road crossing action. Developmental Coordination Disorder (DCD) is a chronic disorder that is characterised by significant motor difficulties that impact on daily living, including a reduced ability to perform visually guided actions. A total of 25 typically developing primary school aged children and 25 age- and gender-matched children with DCD were presented with a virtual desktop task that required them to select suitable temporal crossing gaps between vehicles a stream of traffic approaching at either 20mph, 30mph or 40mph from the near-side (one-lane) or both near+far-sides (two-lane). A best-PEST staircase procedure was used to measure the temporal gaps that children accepted and the maximum likelihood value was taken after nine reversals as each participant's threshold. Typically developing children accepted temporal gaps that were sufficient to execute a safe crossing for vehicles approaching at 20mph and 30mph, but insufficient for vehicles approaching at 40mph. In contrast, children with DCD selected insufficient temporal crossing gaps across all approach speeds, which if translated to the roadside would have resulted in collision. These findings add to our understanding of the difficulties that children with DCD appear to have with visually guided behaviour and suggest the potential impact on one aspect of daily functioning that could have significant consequences.

Diagnosing developmental coordination disorders.

Developmental coordination disorder (DCD) affects around 5% of children and commonly overlaps with other developmental disorders including: attention deficit hyperactivity disorder (ADHD), autism spectrum disorders (ASDs) and specific language impairment (SLI). There is evidence to demonstrate the wide-ranging impact on all areas of functioning including psychiatric and learning domains. There is increasing evidence of the continuing impact into adulthood and the long-term negative effects on relationships and employment. There is a need for early identification and intervention to limit the likelihood of these secondary consequences from emerging. This paper addresses the diagnosis of DCD.

Reduced looming sensitivity in primary school children with Developmental Co-ordination Disorder.

Almost all locomotor animals are sensitive to optical expansion (visual looming) and for most animals this sensitivity is evident very early in their development. In humans there is evidence that responses to looming stimuli begin in the first 6 weeks of life, but here we demonstrate that as children become independent their perceptual acuity needs to be 50 to 100 times better than has been demonstrated in infants in order to be skilful at collision avoidance at a roadside. We have recently established that sensitivity to the detection of visual looming in 6- to 11-year-old children is significantly below that of adults (Wann, Poulter & Purcell, 2011). Here, using comparable methods, we explore looming detection sensitivity in children with Developmental Co-ordination Disorder (DCD), who show broad patterns of impairment in visuo-motor control. We presented visual simulations of approaching vehicles, scaled to represent different approach rates, to children with DCD aged between 6 and 11 years (n = 11) and typically developing age and gender matched controls (n = 11). Looming detection thresholds were measured under foveal and perifoveal viewing conditions, for isotropic expansion and isotropic expansion with simulated viewpoint motion. Our results show that there are situations in which children with DCD may fail to detect vehicles approaching at speeds in excess of 22 km/h, suggesting a developmental immaturity in looming sensitivity. This provides one of the first clear demonstrations of low-level motion processing deficits in children with DCD. The decrement observed may give rise to potential errors in the road crossing behaviour of these children, whereby approaching vehicles could be perceived as stationary. These findings further contribute towards understanding the adverse statistic that children under 9 years of age are four times more likely than adults to be involved in a road accident as a pedestrian.

Reduced sensitivity to visual looming inflates the risk posed by speeding vehicles when children try to cross the road.

Almost all locomotor animals respond to visual looming or to discrete changes in optical size. The need to detect and process looming remains critically important for humans in everyday life. Road traffic statistics confirm that children up to 15 years old are overrepresented in pedestrian casualties. We demonstrate that, for a given pedestrian crossing time, vehicles traveling faster loom less than slower vehicles, which creates a dangerous illusion in which faster vehicles may be perceived as not approaching. Our results from perceptual tests of looming thresholds show strong developmental trends in sensitivity, such that children may not be able to detect vehicles approaching at speeds in excess of 20 mph. This creates a risk of injudicious road crossing in urban settings when traffic speeds are higher than 20 mph. The risk is exacerbated because vehicles moving faster than this speed are more likely to result in pedestrian fatalities.