Elizabeth E. O'Neal

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.

Acting together: Joint pedestrian road crossing in an immersive virtual environment

We investigated how two people jointly coordinate their decisions and actions in a co-occupied, large-screen virtual environment. The task for participants was to physically cross a virtual road with continuous traffic without getting hit by a car. Participants performed this task either alone or with another person (see Fig.1). We found that pairs often crossed the same gap together and closely synchronized their movements when crossing. Pairs also chose larger gaps than individuals to accommodate the extra time needed to cross through gaps together. These results reveal how two people interact and coordinate their behaviors in performing whole-body, joint motions. This study also provides a foundation for future studies examining joint actions in shared VEs where participants are represented by graphic avatars.

Using a virtual environment to study the impact of sending traffic alerts to texting pedestrians

This paper presents an experiment conducted in a large-screen immersive virtual environment to evaluate how texting pedestrians respond to permissive traffic alerts delivered via their cell phone. We developed a cell phone app that delivered information to texting pedestrians about when traffic conditions permit safe crossing. We compared gap selection and movement timing in three groups of pedestrians: texting, texting with alerts, and no texting (control). Participants in the control and alert groups chose larger gaps and were more discriminating in their gap choices than participants in the texting group. Both the control and alert groups had more time to spare than the texting group when they exited the roadway even though the alert group timed their entry relative to the lead car less tightly than the control and texting groups. By choosing larger gaps, participants in the alert group were able to compensate for their poorer timing of entry, resulting in a margin of safety that did not differ from those who were not texting. However, they also relied heavily on the alert system and paid less attention to the roadway. The discussion focuses on the potential of assistive technologies based on Vehicle-to-Pedestrian (V2P) communications technology for mitigating pedestrian-motor vehicle crashes.

Action coordination with agents: crossing roads with a computer-generated character in a virtual environment

We investigated how people jointly coordinate their decisions and actions with a computer-generated character (agent) in a large-screen virtual environment. The task for participants was to physically cross a steady stream of traffic on a virtual road without getting hit by a car. Participants performed this task with another person or with a computer-generated character (Fig. 1). The character was programmed to be either safe (taking only large gaps) or risky (also taking relatively small gaps). We found that participants behaved in many respects similarly with real and virtual partners. They maintained similar distances between themselves and their partner, they often crossed the same gap with their partner, and they synchronized their crossing with their partner. We also found that the riskiness of the character influenced the gap choices of participants. This study demonstrates the potential for using large-screen virtual environments to study how people interact with CG characters when performing whole-body joint actions.

Parent–Child Injury Prevention Conversations Following a Trip to the Emergency Department

OBJECTIVES The goal of the study was to examine how parents use conversation to promote the internalization of safety values after their child has been seriously injured. METHODS Parent interviews detailing postinjury conversations were coded for strategies mentioned to prevent injuries in the future and information about circumstances surrounding the injury. RESULTS Logistic regression analyses revealed that parents were more likely to discuss why an activity was dangerous with older than younger children, and were more likely to urge daughters than sons to be more careful in the future. Injuries resulting from the presence of environmental hazards predicted parents telling children to be more careful in the future. Having others involved predicted parents urging children not to engage in the behavior again. CONCLUSIONS Findings suggest that parents modulated strategies according to age, gender, and injury circumstances to maximize the likelihood that children would behave differently in the future.

The role of Body Mass Index in child pedestrian injury risk

The goal of the current investigation was to examine obesity as a potential risk factor for childhood pedestrian injury. A racially diverse sample of 7- and 8-year-old children completed a road-crossing task in a semi-immersive virtual environment and two pedestrian route selection tasks. Multiple linear regression analyses revealed that children with a higher Body Mass Index (BMI) waited less before crossing, had a smaller temporal buffer between themselves and oncoming traffic while crossing, and had more collisions with traffic. Girls were more cautious than boys when crossing the virtual roadway. Unlike the results from the virtual road-crossing task, BMI was not associated with risky route selection. Instead, race emerged as the strongest predictor, with African-American children selecting riskier routes for crossing. Together, these findings suggest overweight and obese children may be at increased risk for pedestrian injury. The discussion considers explanations for why obese children may exhibit riskier road-crossing behavior.

School Bus Crash Rates on Routine and Nonroutine Routes

BACKGROUND Although prior research has established that school buses are a safe form of transportation, crashes can produce catastrophic consequences. School buses have 2 types of routes: predictable, routine routes that take children to and from school and less predictable, nonroutine routes for school events. No studies have examined school bus crash incidence and characteristics by these route types. METHODS School bus crashes were identified from the Iowa Department of Transportation Crash Database from mid-2005 through mid-2010. Crash reports did not identify whether the bus was on a routine or nonroutine route, so a protocol to assign these based on day and time was developed. Bus mileage was provided by the Iowa Department of Education. RESULTS The school bus crash rate was 2.1 times higher on nonroutine routes than on routine routes (95% CI = 1.8-2.3). Most crashes involved an improper action by the driver of another vehicle. In crashes attributed to improper actions of school buses, failure to yield the right-of-way and disregarding traffic signs were more common on routine routes, while losing control, speeding, reckless, or aggressive driving were more common on nonroutine routes. CONCLUSIONS School bus crashes are more likely to occur on nonroutine routes.

A comparison of head-mounted displays vs. large-screen displays for an interactive pedestrian simulator

This investigation compared how people performed a complex perception-action task - crossing traffic-filled roadways - in a CAVE vs. an HMD virtual environment. Participants physically crossed a virtual roadway with continuous cross traffic in either a CAVE-like or an HTC Vive pedestrian simulator. The 3D model and traffic scenario were identical in both simulators, allowing for a direct comparison between the two display systems. We found that participants in the Vive group accepted smaller gaps for crossing than participants in the CAVE group. They also timed their entry into the gap more precisely and tended to cross somewhat more quickly. As a result, participants in the Vive group had a somewhat larger margin of safety when they exited the roadway than those in the CAVE group. The results provide a foundation for future studies of pedestrian behavior and other tasks involving full-body motion using HMD-based VR.

The influence of stereoscopic image display on pedestrian road crossing in a large-screen virtual environment

This paper investigates the influence of stereoscopic vs. non-stereoscopic display in large-screen virtual environments on an everyday perception-action task - crossing traffic-filled roadways as a pedestrian. The task for participants was to physically cross a virtual road with continuous traffic without getting hit by a car in a CAVE-like virtual environment. Half of the participants performed the task with stereoscopic display and half performed the task with non-stereoscopic display. We found that stereoscopic display had little impact on the size of the gaps participants crossed or the timing of their crossing motion relative to the gap with the exception of a small difference in crossing speed. The results are important for validating the use of non-stereoscopic image displays in ground vehicle simulation and supporting the use of non-stereoscopic displays for multi-viewpoint rendering in co-occupied virtual environments.

Acting Together: Joint Pedestrian Road Crossing in an Immersive Virtual Environment

We investigated how two people jointly coordinate their decisions and actions in a co-occupied, large-screen virtual environment. The task for participants was to physically cross a virtual road with continuous traffic without getting hit by a car. Participants performed this task either alone or with another person (see Fig.1). We found that pairs often crossed the same gap together and closely synchronized their movements when crossing. Pairs also chose larger gaps than individuals to accommodate the extra time needed to cross through gaps together. These results reveal how two people interact and coordinate their behaviors in performing whole-body, joint motions. This study also provides a foundation for future studies examining joint actions in shared VEs where participants are represented by graphic avatars.