Teena M. Garrison

Discoveries from integrating robots into SWAT team training exercises

This research discusses the results of two field evaluations associated with the integration of a ground robot within SWAT team operations. The results indicate that officers preferred having the robot in a Point (first man in) role to having the robot located in the Rear-Guard (last man in) role. The results indicate that the officers reported the robot to be more appealing, trustworthy, cooperative, and helpful in the Point role. They also expressed that they felt less stressed and pressured when the robot was in this role versus having the robot following the team. The robot serving in the Point role was viewed as more integrated with the team and the team liked the robot more than when it was in the Rear-Guard role. The survey results indicate that there were no differences in responses when comparing two different ground robots in the Point role; however during debriefing discussions and from anecdotal comments made by SWAT team officers, a strong preference was expressed for the more rugged, reliable, slower paced Husky A200 robot.

The Effect of Design and Placement of Work-Zone Warning Signs on Driver Speed Compliance: A Simulator-Based Study

OCCUPATIONAL APPLICATIONS In this work, simulated driving was used to test how characteristics of dynamic message signs impact driver behavior when entering designated work zones. Driver compliance with posted speed limits was measured in response to signs that differed in terms of placement distance and type of sign design. Signs should be placed farther ahead of the work zone to enhance speed compliance. Such compliance can also be enhanced by using concise sign content. TECHNICAL ABSTRACT Background and Rationale: In recent years, the number of occupational fatalities occurring as a result of workers being struck by vehicles while on the job has remained high. Fatalities are especially apparent at road construction sites, where nearly half of the fatal occupational injuries were classified as a worker being struck by a moving vehicle, highlighting the need for research to identify techniques to reduce the incidence of injury in future years. Purpose: This project investigated how the characteristics of a dynamic message sign can impact driver compliance with posted information in work-zone settings, specifically signs indicating speed reduction. Methods: Driving simulation was used to assess the effects of three placement distances (305, 457, and 610 m before the work zone) and four sign designs (differing in whether the sign was static versus dynamic and the amount of information presented). The study was completed by 39 participants, during which driving speed and compliance with speed change were recorded. Results: Placement of the speed-reduction signs impacted driver behavior, with greater placement distances being associated with higher speed reduction and compliance rates. Speed reduction was also significantly impacted by sign design, with the largest speed reduction apparent with signs that are static or with dynamic signs that presented one complete statement per display frame. Conclusions: To achieve greater driver compliance with speed limits within work zones, greater sign placement distance is preferred. The content of dynamic message sign needs to be engineered to increase driver compliance by presenting direct, relevant information in concise and complete phrases.

Evaluating pedestrian behavior at crosswalks: Validation of a pedestrian behavior questionnaire for the U.S. population

The aim of this study was to develop and validate a self-reporting Pedestrian Behavior Questionnaire (PBQ) for the U.S. population to measure frequency of risky behaviors among pedestrians. The PBQ includes 50 survey items that allow respondents to rate the frequency with which they engage in different types of road-using behaviors as pedestrians. The validation study was conducted on 425 participants (228 males and 197 females) between the ages of 18 and 71. Confirmatory factor analysis differentiated pedestrian behaviors into five factor categories: violations, errors, lapses, aggressive behaviors, and positive behaviors. A short version of the PBQ with 20 items was also created by selecting four items with high factor loadings from each of the five factor categories. Regression analyses investigated associations with scenario-based survey behavioral responses to validate the five-factor PBQ subscale scores and composite score. For both long and short versions, each of these five individual factor scales were found to be reliable (0.7<Cronbachs alpha (α)<0.9) and valid (significant association with p<0.0001), except in the case of positive behaviors (α<0.6) which requires further expansion. The effects of gender and age on the PBQ scores were investigated and found to be consistent with previous research. This PBQ can serve as an instrument of pedestrian self-assessment in educational and training contexts as well as can be useful to all researchers investigating pedestrian safety for all age groups.

A Quantitative Comparison of Operator Field of View for Vehicle Design

This paper outlines the preliminary application of a quantitative method for assessing field of view using spherical projections of categorical visual information overlaid by occlusion maps based on vehicle geometry. The project goal was to quantitatively assess not only where a vehicle operator can see but what visual information is available in the operator’s field of view. By creating a driving environment dataset coded for visual information, we can indicate the probability of a type of visual information appearing in the operator’s field of view in a given vehicle. Next, we overlay probability maps with vehicle and operator eye height-specific occlusion maps, giving us a quantitative representation of visible information. This method was applied to three vehicles: a midsized sedan, a light-duty pickup truck, and a full-sized pickup truck using eye heights corresponding to those of 5th percentile females, 50th percentile females, 50th percentile males, and 95th percentile males.

Conducting a Prospective Review for Enhanced Interface Features for Unmanned Ground Vehicle Operation

When developing new interface features, it is vital to consider the perspectives of users from several backgrounds throughout the process, in order to ensure features that address realistic user concerns in effective ways. The Systematic Human Error Reduction and Prediction Approach (SHERPA) and an established user acceptance questionnaire were used to evaluate the predicted usability and acceptability of four enhanced interface features for unmanned ground vehicle (UGV) operation. The targeted interface is designed for use in real-world and simulated environments. Although the SHERPA results alone did not clearly distinguish between interface enhancements, the user acceptance results from team members converged on a single ‘best’ interface enhancement for supporting collision avoidance and navigation, based on assessments using early mock-ups in a simulated environment.

Initial Performance Assessment of a Control Interface for Unmanned Ground Vehicle Operation Using a Simulation Platform

The successful navigation of Unmanned ground vehicles (UGV) is important as UGVs are being increasingly integrated into tactical and reconnaissance operations. Not only is there the possibility of winding environments but also the narrow passage of obstacles. This study investigated a participant’s ability to navigate a maze environment incorporating narrow hallways, with two different user interfaces, using human in the loop simulation. Participants used a game controller and customized user interface to navigate a simulated UGV through a simulated maze environment. Results indicated that the video-plus-map interface displaying both video and LiDAR data required more time to complete compared to an interface displaying video-only data.

Optimizing Training for Visual Discrimination Across Stimulus Categories

Discriminating between stimuli is a component of many complex tasks such as radar operations and flying an F-16. Previous research suggests that initial training difficulty may influence the acquisition and transfer of strategic discrimination skills for such tasks. The current research examined the extent to which strategies acquired during initial training may be transferred to novel stimuli. Participants were trained to discriminate between similar (difficult training) or dissimilar (easy training) stimuli and then were required to discriminate between completely novel stimuli. Of specific interest were the effects of strategic skills acquired in a difficult- or easy-training context on inter-categorical transfer performance. The results provided further evidence that initial training difficulty influences strategic skill acquisition and suggest that strategic skills are applied at transfer, even to a completely novel category of stimuli. The implications of this research are discussed in the context of learning theories and training.