The risk of major occupational accidents involving tripping hazards is commonly underestimated with a large number of studies having been conducted to better understand variables that affect situation awareness: the ability to detect, perceive, and comprehend constantly evolving surroundings. An important property that affects situation awareness is the limited capacity of the attentional system. To maintain situation awareness while exposed to tripping hazards, a worker needs to obtain feedforward information about hazards, detect immediate tripping hazards, and visually scan surroundings for any potential environmental hazards. Despite the importance of situation awareness, its relationship with attention remains unknown in the construction industry. To fill this theoretical knowledge gap, this study examines differences in attentional allocation between workers with low and high situation awareness levels while exposed to tripping hazards in a real construction site. Participants were exposed to tripping hazards on a real jobsite while walking along a path in the presence of other workers. Situation awareness was measured using the situation awareness rating technique, and subjects' eye movements were tracked as direct measures of attention via a wearable mobile eye tracker. Investigating the attentional distribution of subjects by examining fixation-count heat maps and scan paths revealed that as workers with higher situation awareness walked, they periodically looked down and scanned ahead to remain fully aware of the environment and its associated hazards. Furthermore, this study quantitatively compared the differences between the eye-tracking metrics of worker with different situation awareness levels (low versus high) using permutation simulation. The results of the statistical analysis indicate that subjects did not allocate their attention equally to all hazardous areas of interest, and these differences in attentional distribution were modulated by the workers' level of situation awareness. This study advances theory by presenting one of the first attempts to use mobile eye-tracking technology to examine the role of cognitive processes (i.e., attention) in human error (i.e., failure to identify a hazard) and occupational accidents.

Although several studies have highlighted the importance of attention in reducing the number of injuries in the construction industry, few have attempted to empirically measure the attention of construction workers. One technique that can be used to measure worker attention is eye tracking, which is widely accepted as the most direct and continuous measure of attention because where one looks is highly correlated with where one is focusing his or her attention. Thus, with the fundamental objective of measuring the impacts of safety knowledge (specifically, training, work experience, and injury exposure) on construction workers' attentional allocation, this study demonstrates the application of eye tracking to the realm of construction safety practices. To achieve this objective, a laboratory experiment was designed in which participants identified safety hazards presented in 35 construction site images ordered randomly, each of which showed multiple hazards varying in safety risk. During the experiment, the eye movements of 27 construction workers were recorded using a head-mounted EyeLink II system. The impact of worker safety knowledge in terms of training, work experience, and injury exposure (independent variables) on eyetracking metrics (dependent variables) was then assessed by implementing numerous permutation simulations. The results show that tacit safety knowledge acquired from work experience and injury exposure can significantly improve construction workers' hazard detection and visual search strategies. The results also demonstrate that (1) there is minimal difference, with or without the Occupational Safety and Health Administration 10-h certificate, in workers' search strategies and attentional patterns while exposed to or seeing hazardous situations; (2) relative to less experienced workers (<5 years), more experienced workers (>10 years) need less processing time and deploy more frequent short fixations on hazardous areas to maintain situational awareness of the environment; and (3) injury exposure significantly impacts a worker's visual search strategy and attentional allocation. In sum, practical safety knowledge and judgment on a jobsite requires the interaction of both tacit and explicit knowledge gained through work experience, injury exposure, and interactive safety training. This study significantly contributes to the literature by demonstrating the potential application of eye-tracking technology in studying the attentional allocation of construction workers. Regarding practice, the results of the study show that eye tracking can be used to improve worker training and preparedness, which will yield safer working conditions, detect at-risk workers, and improve the effectiveness of safety-training programs. ; separate discussions must be submitted for individual papers. This paper is part of the Journal of Management in Engineering, © ASCE, ISSN 0742-597X. © ASCE 04017024-1 J. Manage. Eng. J. Manage. Eng., -1--1 Downloaded from ascelibrary.org by Behzad Esmaeili on 04/12/17. Copyright ASCE....

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Eye-movement metrics have been shown to correlate with attention and, therefore, represent a means of identifying and analyzing an individual's cognitive processes. Human errors-such as failure to identify a hazard-are often attributed to a worker's lack of attention. Piecemeal attempts have been made to investigate the potential of harnessing eye movements as predictors of human error (e.g., failure to identify a hazard) in the construction industry, although more attempts have investigated human error via subjective measurements. To address this knowledge gap, the present study harnessed eye-tracking technology to evaluate the impacts of workers' hazard-identification skills on their attentional distributions and visual search strategies. To achieve this objective, an experiment was designed in which the eye movements of 31 construction workers were tracked while they searched for hazards in 35 randomly ordered construction scenario images. Workers were then divided into three groups on the basis of their hazard identification performance. Three fixation-related metrics-fixation count, dwell-time percentage, and run count-were analyzed during the eye-tracking experiment for each group (low, medium, and high hazard-identification skills) across various types of hazards. Then, multivariate ANOVA (MANOVA) was used to evaluate the impact of workers' hazard-identification skills on their visual attention. To further investigate the effect of hazard identification skills on the dependent variables (eye movement metrics), two distinct processes followed: separate ANOVAs on each of the dependent variables, and a discriminant function analysis. The analyses indicated that hazard identification skills significantly impact workers' visual search strategies: workers with higher hazard-identification skills had lower dwell-time percentages on ladder-related hazards; higher fixation counts on fall-to-lower-level hazards; and higher fixation counts and run counts on fall-protection systems, struck-by, housekeeping, and all hazardous areas combined. Among the eye-movement metrics studied, fixation count had the largest standardized coefficient in all canonical discriminant functions, which implies that this eye-movement metric uniquely discriminates workers with high hazard-identification skills and at-risk workers. Because discriminant function analysis is similar to regression, discriminant function (linear combinations of eye-movement metrics) can be used to predict workers' hazard-identification capabilities. In conclusion, this study provides a proof of concept that certain eyemovement metrics are predictive indicators of human error due to attentional failure. These outcomes stemmed from a laboratory setting, and, foreseeably, safety managers in the future will be able to use these findings to identify at-risk construction workers, pinpoint required safety training, measure training effectiveness, and eventually improve future personal protective equipment to measure construction workers' situation awareness in real time.

Workers' attentional failures or inattention toward detecting a hazard can lead to inappropriate decisions and unsafe behaviors. Previous research has shown that individual characteristics such as past injury exposure contribute greatly to skill-based (e.g., attention failure) and perception-based (e.g., failure to identify and misperception) errors and subsequent accident involvement. However, a dearth of research empirically examined how a worker's personality affects his or her attention and hazard identification. This study addresses this knowledge gap by exploring the impacts of the personality dimensions on the selective attention of workers exposed to fall hazards. To this end, construction workers were recruited to engage in a laboratory eye-tracking experiment that consisted of 115 potential and active fall scenarios in 35 construction images captured from actual projects within the United States. Construction workers' personalities were assessed through the self-completion of the Big Five personality questionnaire, and their visual attention was monitored continuously using a wearable eye-tracking apparatus. The results of the study show that workers' personality dimensions-specifically, extraversion, conscientiousness, and openness to experience-significantly relate to and impact attentional allocations and the search strategies of workers exposed to fall hazards. A more detailed investigation of this connection showed that individuals who are introverted, more conscientious, or more open to experience are less prone to injury and return their attention more frequently to hazardous areas. This study is the first attempt to illustrate how examining relationships among personality, attention, and hazard identification can reveal opportunities for the early detection of at-risk workers who are more likely to be involved in accidents. A better understanding of these connections provides valuable insight into both practice and theory regarding the transformation of current training and educational practices by providing appropriate intervention strategies for personalized safety guidelines and effective training materials to transform personality-driven at-risk workers into safer workers.