A Feasibility Randomized Trial Evaluating Safe Peds: A Virtual Reality Training Program to Teach Children When to Cross Streets Safely

OBJECTIVE

Injury as pedestrians is a leading contributor to childhood deaths. This study evaluated the effectiveness of Safe Peds, a fully immersive virtual reality training program to teach children when to cross street safely, with the focus on a number of foundational skills and practicing these in traffic situations of varying complexity.

METHODS

Children 7-10 years old were randomly assigned to a control (N = 31) or intervention (N = 26) group. Eligibility criteria included English speaking and typically developing. Testing took place on campus. All children completed pre- and post-testing measures, with those in the intervention group receiving training in between. Training comprised 1 session with 3 phases for a total of up to 1.5 hr and was tailored to each child's performance over trials. On each trial, children decided when to cross and fully executed this crossing, with measures automatically taken by the system as they did so.

RESULTS

Negative binomial regression and analysis of covariance tests were applied, predicting post-test scores while controlling for pre-test scores, age, and sex. The intervention was effective in improving children's street crossing skills, including stopping and checking skills (stop at the curb, look left/right/left, check for traffic before crossing the yellow line), and choosing safe inter-vehicle gaps. Children in the control group did not show significant improvements in any crossing skills.

CONCLUSIONS

The Safe Peds program effectively teaches children skills to support their deciding when to safely cross in a variety of traffic situations. Implications for pedestrian injury are discussed.

Effects of Initial Starting Distance and Gap Characteristics on Children's and Young Adults' Velocity Regulation When Intercepting Moving Gaps

OBJECTIVE

This study investigated how children and young adults regulate their velocity when crossing roads under varying traffic conditions.

BACKGROUND

To cross roads safely, pedestrians must adapt their movements to the moving vehicles around them while tightly coupling their movement to visual information.

METHOD

Using an Oculus Rift, 16 children and 16 young adults walked on a treadmill and intercepted gaps between two simulated moving vehicles in an immersive virtual environment. We varied the participants' initial distance from the curb to the interception point, as well as gap characteristics, including gap size and vehicle size.

RESULTS

Varying the initial distance led to systematic adjustments in participants' approach velocities. The inter-vehicle gap and the vehicle size affected the crossing position induced by the initial distance. However, participants did not systematically scale their positions according to the initial distance in narrow gap. Notably, children did not finely tune their movements when they approached wide gap from a closer distance or when they approached the large vehicle from closer distance.

CONCLUSION

Children were less precise in coupling their movements to the moving vehicle in complex traffic environments. In particular, large moving vehicles approaching at closer distances can pose risks when children cross roads.

APPLICATION

These findings suggest the need for an intervention program to improve children's skill in perceiving larger vehicles and timing their movements when crossing roads. We suggest using an interactive virtual reality system to practice this skill.

Behavioral Dynamics of Pedestrians Crossing between Two Moving Vehicles

This study examines the human behavioral dynamics of pedestrians crossing a street with vehicular traffic. To this end, an experiment was constructed in which human participants cross a road between two moving vehicles in a virtual reality setting. A mathematical model is developed in which the position is given by a simple function. The model is used to extract information on each crossing by performing root-mean-square deviation (RMSD) minimization of the function from the data. By isolating the parameter adjusted to gap features, we find that the subjects primarily changed the timing of the acceleration to adjust to changing gap conditions, rather than walking speed or duration of acceleration. Moreover, this parameter was also adjusted to the vehicle speed and vehicle type, even when the gap size and timing were not changed. The model is found to provide a description of gap affordance via a simple inequality of the fitting parameters. In addition, the model turns out to predict a constant bearing angle with the crossing point, which is also observed in the data. We thus conclude that our model provides a mathematical tool useful for modeling crossing behaviors and probing existing models. It may also provide insight into the source of traffic accidents.

Roles of individual differences and traffic environment factors on children's street-crossing behaviour in a VR environment

OBJECTIVE

Pedestrian injuries are among the most common cause of death and serious injury to children. A range of risk factors, including individual differences and traffic environment factors, has been investigated as predictors of children's pedestrian behaviours. There is little evidence examining how risk factors might interact with each other to influence children's risk, however. The present study examined the independent and joint influences of individual differences (sex and sensation seeking) and traffic environment factors (vehicle speeds and inter-vehicle distances) on children's pedestrian safety.

METHODS

A total of 300 children aged 10-13 years were recruited to complete a sensation-seeking scale, and 120 of those were selected for further evaluation based on having high or low sensation-seeking scores in each gender, with 30 children in each group. Children's pedestrian crossing behaviours were evaluated in a virtual reality traffic environment.

RESULTS

Children low in sensation seeking missed more opportunities to cross and had longer start gaps to enter the roadway compared with those high in sensation seeking, and these effects were more substantial when vehicles were spread further apart but travelling slowly. Interaction effects between inter-vehicle distance and vehicle speed were also detected, with children engaging in riskier crossings when the car was moving more quickly and the vehicles were spread further than when the vehicles were moving quickly but were closer together. No sex differences or interactions emerged.

CONCLUSION

Both sensation seeking and traffic environment factors impact children's behaviour in traffic, and there are interactions between traffic speeds and inter-vehicle distances that impact crossing behaviour.

Timing Is Almost Everything: How Children Perceive and Act on Dynamic Affordances

A key challenge for the developing perception-action system is learning how to move the self in relation to other moving objects. This often involves perceiving and acting on affordances or possibilities for action that depend on the relation between the characteristics of the individual and the properties of the environment (Gibson, 1979). This chapter overviews our program of research on perceiving and acting on dynamic affordances (i.e., possibilities for action that vary over time). Our goal is to bridge the divide between basic and applied research by using road crossing as a model system for studying how children's ability to perceive and act on dynamic affordances undergoes change with age and experience. The basic task is for participants to cross virtual roads with continuous traffic either on foot or on a bicycle. This work reveals that children's gap choices and crossing motions are less tightly linked than those of adults. Children often choose the same size gaps as adults but time their entry into those gaps less tightly than adults. As a result, children typically end up with less time to spare than adults when they clear the path of the vehicles. Improvement in gap selection and movement timing occurs gradually over development, indicating the perception-action system undergoes continuous change well into adolescence. As in other areas of development (e.g., face perception, word recognition), this kind of gradual developmental change appears critical for the fine-tuning of the system. The late development of these skills may explain also why adolescent pedestrians, cyclists, and drivers continue to be at risk for collisions when crossing roads. Further work aimed at better understanding the developmental mechanisms underlying these changes will inform the fields of both developmental science and injury prevention.

Changes in perception-action tuning over long time scales: How children and adults perceive and act on dynamic affordances when crossing roads

This investigation examined developmental change in how children perceive and act on dynamic affordances when crossing roads on foot. Six- to 14-year-olds and adults crossed roads with continuous cross-traffic in a large-screen, immersive pedestrian simulator. We observed change both in children's gap choices and in their ability to precisely synchronize their movement with the opening of a gap. Younger children were less discriminating than older children and adults, choosing fewer large gaps and more small gaps. Interestingly, 12-year-olds' gap choices were significantly more conservative than those of 6-, 8-, 10-, and 14-year-olds, and adults. Timing of entry behind the lead vehicle in the gap (a key measure of movement coordination) improved steadily with development, reaching adultlike levels by age 14. Coupled with their poorer timing of entry, 6-, 8-, and 10-year-olds' gap choices resulted in significantly less time to spare and more collisions than 14-year-olds and adults. Time to spare did not differ between 12-year-olds, 14-year-olds, and adults, indicating that 12-year-olds' more conservative gap choices compensated for their poorer timing of entry. The findings show that children's ability to perceive and act on dynamic affordances undergoes a prolonged period of development, and that older children appear to compensate for their poorer movement timing skills by adjusting their gap decisions to match their crossing actions. Implications for the development of perception-action tuning and road-crossing skills are discussed. (PsycINFO Database Record

Virtual reality by mobile smartphone: improving child pedestrian safety

BACKGROUND

Pedestrian injuries are a leading cause of paediatric injury. Effective, practical and cost-efficient behavioural interventions to teach young children street crossing skills are needed. They must be empirically supported and theoretically based. Virtual reality (VR) offers promise to fill this need and teach child pedestrian safety skills for several reasons, including: (A) repeated unsupervised practice without risk of injury, (B) automated feedback on crossing success or failure, (C) tailoring to child skill levels: (D) appealing and fun training environment, and (E) most recently given technological advances, potential for broad dissemination using mobile smartphone technology.

OBJECTIVES AND METHODS

Extending previous work, we will evaluate delivery of an immersive pedestrian VR using mobile smartphones and the Google Cardboard platform, technology enabling standard smartphones to function as immersive VR delivery systems. We will overcome limitations of previous research suggesting children learnt some pedestrian skills after six VR training sessions but did not master adult-level pedestrian skills by implementing a randomised non-inferiority trial with two equal-sized groups of children ages 7-8 years (total N=498). All children will complete baseline, postintervention and 6-month follow-up assessments of pedestrian safety and up to 25 30-min pedestrian safety training trials until they reach adult levels of functioning. Half the children will be randomly assigned to train in Google Cardboard and the other half in a semi-immersive kiosk VR. Analysis of Covariance (ANCOVA) models will assess primary outcomes.

DISCUSSION

If results are as hypothesised, mobile smartphones offer substantial potential to overcome barriers of dissemination and implementation and deliver pedestrian safety training to children worldwide.

Using a Virtual Environment to Examine How Children Cross Streets: Advancing Our Understanding of How Injury Risk Arises

PURPOSE

To examine how risk of injury can arise for child pedestrians.

METHODS

Using a highly immersive virtual reality system interfaced with a 3-D movement measurement system, younger (M = 8 years) and older (M = 10 years) children's crossing behaviors were measured under conditions that introduced variation in vehicle speed, distance, and intervehicle gaps.

RESULTS

Children used distance cues in deciding when to cross; there were no age or sex differences. This increased risk of injury in larger intervehicle gaps because they started late and did not monitor traffic or adjust walking speed as they crossed. In contrast, injury risk in smaller intervehicle gaps of equal risk (i.e., same time to contact) occurred because crossing behavioral adjustments (starting early, increasing walking speed while crossing) were not sufficient.

CONCLUSIONS

Dependence on distance cues increases children's risk of injury as pedestrians when crossing in a variety of traffic situations.

How children and adults learn to intercept moving gaps

We used an immersive virtual environment to examine how children and adults learn to intercept moving gaps and whether children and adults benefit from variability of practice. Children (10- and 12-year-olds) and adults attempted to bicycle between two moving vehicle-size blocks without stopping. In Experiment 1, block motions were timed such that if participants maintained a constant speed, they would intercept the gap between the blocks. By the last set of intersections, adults learned to maintain a constant speed throughout the approach to the intersection, 12-year-olds exhibited less variability in time-to-spare when they intercepted the blocks, and 10-year-olds exhibited no significant change across intersection sets. In Experiment 2, block motions during the first eight intersections were timed such that participants needed to either speed up or slow down on all intersections or needed to speed up on half and slow down on half of the intersections. On the last four intersections, all age groups encountered a novel block timing in which no adjustment in speed was necessary to intercept the blocks. The adults performed well regardless of whether they experienced consistent or variable block timings. The 10-year-olds in the variable condition performed better on slow-down trials than their peers in the slow-down condition but performed worse on speed-up trials than their peers in the speed-up condition. Discussion focuses on possible developmental changes in reliance on perceptually available and remembered information in complex perception-action tasks.