Developing attentional control in naturalistic dynamic road crossing situations

Analysis of pedestrian-two-wheeler conflicts at green light digital countdown signals: A random parameter ordered logit model approach

The rising prevalence of e-bikes and shared bikes in transportation modes adds complexity to pedestrian movement at intersections. The conflict technique is a substitute for collisions in analyzing pedestrian safety at digital countdown signal intersections. Pedestrian and two-wheeler trajectories were obtained using Unmanned Aerial Vehicle (UAV) and T-Analyst software. The severity of pedestrian-two-vehicle conflicts was assessed using indicators such as Time to Collision (TTC), Post Encroachment Time (PET), and Yaw Rate Ratio (YRR), along with the fuzzy C-mean clustering method. An analysis of the impact of pedestrian characteristics, cyclist characteristics, and road conflict factors on severity was conducted using a random parameter ordered logit model. A total of 630 valid conflicts were identified, comprising 105 potential conflicts, 242 minor conflicts, and 283 serious conflicts. More minor and serious conflicts occurred in Signal 1 and Signal 2. Serious conflicts mainly occurred in road Zone 2, Zone 3, and Zone 5, while minor conflicts were more frequent in Zone 4 and Zone 5. Pedestrian crossing at Signal 2 increased the conflict severity, and the refuge island had a similar effect. Cyclists passing the conflict point first reduced the probability of serious conflicts. Older adults are safer at countdown signal intersections than young people. It is essential to enhance the awareness of digital countdown signals among youth. Managers should consider diverting two-wheelers during peak hours and encourage cyclists to walk through crosswalks.

Developmental differences in children's adaptation to vehicle distance and speed in street-crossing decision-making

INTRODUCTION

Young children cannot effectively adapt their behaviors to vehicles at varied distances and speeds, which is a critical cause of road accidents. However, the impact of this crucial ability on children's street-crossing decision-making and the age at which they acquire it remain unclear.

METHOD

This study examined the crossing decision-making behavior of children at 6, 8, and 11 years of age in facing 51 different videotaped traffic scenarios with varying vehicle distances and speeds. Sixty Chinese elementary school students, with 20 children evenly distributed into each of the three age groups (6 years, 8 years, and 11 years old), participated in a simulated street-crossing task using video projections. Hierarchical logistic regression models were used to analyze how age moderated the effects of vehicular motion factors (vehicle-pedestrian distance, vehicle speed) on children's crossing safety, including dangerous crossing and crossing decision-making.

RESULTS

The results showed that when either vehicle-pedestrian distance decreased or vehicle speed increased all age groups tended to cross less frequently but probability of dangerous crossing increased. Compared to 8-year-old and 11-year-old children, 6-year-old children showed a less pronounced tendency toward both of these crossing decision-making behaviors, and had more dangerous crossing outcomes.

CONCLUSIONS

These findings suggest that inadequate adaptation to vehicle-pedestrian distance and vehicle speed may partly contribute to the inferior safety of street-crossing behavior in 6-year-olds compared to 8-year-olds. No significant differences were observed between 8- and 11-year-old children, suggesting the turning point for this ability might occur between 6 and 8 years of age.

PRACTICAL APPLICATIONS

Preventive measures aimed to reduce crossing risks for children should consider children's developmental stages.

The impact of perceptual complexity on road crossing decisions in younger and older adults

Cognitive abilities decline with healthy ageing which can have a critical impact on day-to-day activities. One example is road crossing where older adults (OAs) disproportionally fall victim to pedestrian accidents. The current research examined two virtual reality experiments that investigated how the complexity of the road crossing situation impacts OAs (N = 19, ages 65-85) and younger adults (YAs, N = 34, ages 18-24) with a range of executive functioning abilities (EFs). Overall, we found that OAs were able to make safe crossing decisions, and were more cautious than YAs. This continued to be the case in high cognitive load situations. In these situations, safe decisions were associated with an increase in head movements for participants with poorer attention switching than participants with better attention switching suggesting these groups developed compensation strategies to continue to make safe decisions. In situations where participants had less time to make a crossing decision all participants had difficulties making safe crossing decisions which was amplified for OAs and participants with poorer EFs. Our findings suggest more effort should be taken to ensure that road crossing points are clear of visual obstructions and more speed limits should be placed around retirement or care homes, neither of which are legislated for in the UK and Australia.

Do Real-Time Strategy Video Gamers Have Better Attentional Control?

OBJECTIVE

Do real-time strategy (RTS) video gamers have better attentional control? To examine this issue, we tested experienced versus inexperienced RTS video gamers on multi-object tracking tasks (MOT) and dual-MOT tasks with visual or auditory secondary tasks (dMOT). We employed a street-crossing task with a visual working memory task as a secondary task in a virtual reality (VR) environment to examine any generalized attentional advantage.

BACKGROUND

Similar to action video games, RTS video games require players to switch attention between multiple visual objects and views. However, whether the attentional control advantage is limited by sensory modalities or generalizes to real-life tasks remains unclear.

METHOD

In study 1, 25 RTS video game players (SVGP) and 25 non-video game players (NVGP) completed the MOT task and two dMOT tasks. In study 2, a different sample with 25 SVGP and 25 NVGP completed a simulated street-crossing task with the visual dual task in a VR environment.

RESULTS

After controlling the effects of the speed-accuracy trade-off, SVGP showed better performance than NVGP in the MOT task and the visual dMOT task, but SVGP did not perform better in either the auditory dMOT task or the street-crossing task.

CONCLUSION

RTS video gamers had better attentional control in visual computer tasks, but not in the auditory tasks and the VR tasks. Attentional control benefits associated with RTS video game experience may be limited by sensory modalities, and may not translate to performance benefits in real-life tasks.

Road-Crossing Behavior in Complex Traffic Situations: A Comparison of Children With and Without ADHD

All children are vulnerable to pedestrian injuries, but previous research suggests children diagnosed with ADHD may have elevated risk. Child pedestrian injury risk also increases with increasing traffic volume and speed. The current study examined three hypotheses: (a) Pedestrian behavior of children with ADHD is riskier than that of typically-developing children; (b) Children's pedestrian behavior is riskier with increased traffic complexity; and (c) Pedestrian behavior of children with ADHD is influenced more by complex traffic situations than behavior of typically-developing children. A sample of 38 children ages 8-12 years, 45% diagnosed with ADHD, completed 21 virtual street-crossings, 7 in each of three levels of traffic complexity. Outcome measures included unsafe crossings, ratio of looking at traffic by time, start-delay to enter the road, time to contact with oncoming vehicles, and time waiting to cross. A repeated measure MANOVA and follow-up tests showed that all children had more unsafe crossings, shorter start-delays and shorter TTCs when exposed to increased traffic complexity compared to lighter traffic. Children with ADHD had more unsafe crossings than typically-developing children. Further, compared to typically-developing children, ADHD children had comparatively more unsafe crossings, lower time to contact and longer wait-time in more complex traffic environments. Executive function deficits among children with ADHD likely influence their behavior in complex traffic environments. Implications of the results for policy-making and preventive strategies are discussed.

Modeling eye movement in dynamic interactive tasks for maximizing situation awareness based on Markov decision process

For complex dynamic interactive tasks (such as aviating), operators need to continuously extract information from areas of interest (AOIs) through eye movement to maintain high level of situation awareness (SA), as failures of SA may cause task performance degradation, even system accident. Most of the current eye movement models focus on either static tasks (such as image viewing) or simple dynamic tasks (such as video watching), without considering SA. In this study, an eye movement model with the goal of maximizing SA is proposed based on Markov decision process (MDP), which is designed to describe the dynamic eye movement of experienced operators in dynamic interactive tasks. Two top-down factors, expectancy and value, are introduced into this model to represent the update probability and the importance of information in AOIs, respectively. In particular, the model regards sequence of eye fixations to different AOIs as sequential decisions to maximize the SA-related reward (value) in the context of uncertain information update (expectancy). Further, this model was validated with a flight simulation experiment. Results show that the predicted probabilities of fixation on and shift between AOIs are highly correlated (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$R = 0.928$$\end{document}R=0.928 and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$R = 0.951$$\end{document}R=0.951, respectively) with those of the experiment data.

The Relative Contribution of Executive Functions and Aging on Attentional Control During Road Crossing

As we age, many physical, perceptual and cognitive abilities decline, which can critically impact our day-to-day lives. However, the decline of many abilities is concurrent; thus, it is challenging to disentangle the relative contributions of different abilities in the performance deterioration in realistic tasks, such as road crossing, with age. Research into road crossing has shown that aging and a decline in executive functioning (EFs) is associated with altered information sampling and less safe crossing decisions compared to younger adults. However, in these studies declines in age and EFs were confounded. Therefore, it is impossible to disentangle whether age-related declines in EFs impact on visual sampling and road-crossing performance, or whether visual exploration, and road-crossing performance, are impacted by aging independently of a decline in EFs. In this study, we recruited older adults with maintained EFs to isolate the impacts of aging independently of a decline EFs on road crossing abilities. We recorded eye movements of younger adults and older adults while they watched videos of road traffic and were asked to decide when they could cross the road. Overall, our results show that older adults with maintained EFs sample visual information and make similar road crossing decisions to younger adults. Our findings also reveal that both environmental constraints and EF abilities interact with aging to influence how the road-crossing task is performed. Our findings suggest that older pedestrians' safety, and independence in day-to-day life, can be improved through a limitation of scene complexity and a preservation of EF abilities.

Research on intervention methods for children's street-crossing behaviour: Application and expansion of the theory of "behaviour spectrums"

Due to immaturity in their physical and cognitive development, children are particularly vulnerable to road traffic injuries as pedestrians. Child pedestrian injury primarily occurs in urban areas, with a significant share at crosswalks. The aim of this study is to explore whether an intervention programme based on the theory of "behaviour spectrums" can improve the street-crossing skills of primary school children. Children were recruited near a local primary school through invitation letters and were randomly divided into two groups: a control group (n = 10, no intervention) and an experimental group (n = 10, intervention). The children in the experimental group received 30-45 min of training. The child participants were asked to wear an eye tracker and performed a crossing test in a real-world street environment; in this test, they were required to successively pass through an unsignalised intersection, an unsignalised T-intersection and a signalised intersection on a designated test route. A high-definition camera was used to record the children's crossing behaviour, and the Tobii Pro Glasses 2 eye tracker was used to derive indicators of the children's visual behaviour in the areas of interest (AOIs) in the street. The evaluation was conducted on children's crossing behaviour in the control group (which received no intervention) and the experimental group (tested at two time points after the intervention: children tested immediately after the intervention and children retested one month after the intervention). The results showed that compared with the control group, the children in the experimental group no longer focused on the small area around the body (e.g., the zebra crossing area) and the area in front of the eyes (e.g., the sidewalk area), which increased their visual attention to the traffic areas on the left and right sides of the zebra crossing; thus, unsafe crossing behaviour was reduced in the experimental group. Compared with the experimental group immediately after the intervention, the intervention effect on some indicators showed a significant weakening trend in the retest of the experimental group one month later. Overall, the results show that an intervention programme based on the theory of "behaviour spectrums" can improve children's crossing skills. This study provides valuable information for the development and evaluation of intervention programmes to improve children's street-crossing skills.

Safety envelope of pedestrians upon motor vehicle conflicts identified via active avoidance behaviour

Human reaction plays a key role in improved protection upon emergent traffic situations with motor vehicles. Understanding the underlying behaviour mechanisms can combine active sensing system on feature caption and passive devices on injury mitigation for automated vehicles. The study aims to identify the distance-based safety boundary (“safety envelope”) of vehicle–pedestrian conflicts via pedestrian active avoidance behaviour recorded in well-controlled, immersive virtual reality-based emergent traffic scenarios. Via physiological signal measurement and kinematics reconstruction of the complete sequence, we discovered the general perception-decision-action mechanisms under given external stimulus, and the resultant certain level of natural harm-avoidance action. Using vision as the main information source, 70% pedestrians managed to avoid the collision by adapting walking speeds and directions, consuming overall less “decision” time (0.17–0.24 s vs. 0.41 s) than the collision cases, after that, pedestrians need enough “execution” time (1.52–1.84 s) to take avoidance action. Safety envelopes were generated by combining the simultaneous interactions between the pedestrian and the vehicle. The present investigation on emergent reaction dynamics clears a way for realistic modelling of biomechanical behaviour, and preliminarily demonstrates the feasibility of incorporating in vivo pedestrian behaviour into engineering design which can facilitate improved, interactive on-board devices towards global optimal safety.

In pursuit of visual attention: SSVEP frequency-tagging moving targets

Previous research has shown that visual attention does not always exactly follow gaze direction, leading to the concepts of overt and covert attention. However, it is not yet clear how such covert shifts of visual attention to peripheral regions impact the processing of the targets we directly foveate as they move in our visual field. The current study utilised the co-registration of eye-position and EEG recordings while participants tracked moving targets that were embedded with a 30 Hz frequency tag in a Steady State Visually Evoked Potentials (SSVEP) paradigm. When the task required attention to be divided between the moving target (overt attention) and a peripheral region where a second target might appear (covert attention), the SSVEPs elicited by the tracked target at the 30 Hz frequency band were significantly, but transiently, lower than when participants did not have to covertly monitor for a second target. Our findings suggest that neural responses of overt attention are only briefly reduced when attention is divided between covert and overt areas. This neural evidence is in line with theoretical accounts describing attention as a pool of finite resources, such as the perceptual load theory. Altogether, these results have practical implications for many real-world situations where covert shifts of attention may discretely reduce visual processing of objects even when they are directly being tracked with the eyes.