Sidewalk potential trip points: A method for characterizing walkways

Ayres, Thomas J.; Kelkar, Rajeev

doi:10.1016/j.ergon.2006.09.004

Cited by 18 publications

(19 citation statements)

References 9 publications

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“…Workers obtain feedforward information about potential sources of tripping hazards several feet ahead of them by directing their gaze downward (Land 2006;Kuzel et al 2013;Ayres and Kelkar 2006;Buckley et al 2011). This distance-or "effective visual field"-is often 3 m ahead and slightly below horizontal (Whetsel and Campbell 2016).…”

Section: Role Of Attention In Situation Awarenessmentioning

confidence: 99%

Examining the Relationship between Construction Workers’ Visual Attention and Situation Awareness under Fall and Tripping Hazard Conditions: Using Mobile Eye Tracking

Hasanzadeh

Esmaeili

Dodd

2018

J. Constr. Eng. Manage.

138

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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.

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Section: Role Of Attention In Situation Awarenessmentioning

confidence: 99%

Examining the Relationship between Construction Workers’ Visual Attention and Situation Awareness under Fall and Tripping Hazard Conditions: Using Mobile Eye Tracking

Hasanzadeh

Esmaeili

Dodd

2018

J. Constr. Eng. Manage.

138

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“…If an obstacle is seen, subjects will increase MTC to avoid contacting it [22]. Although it may seem unreasonable that an individual would trip over an obstacle of only several millimeters, it seems more likely that a smaller obstacle would go unnoticed, and smaller obstacles may be more common than larger ones [42]. Over a 1 mi residential sidewalk, there may be as many as 30 trip-points of 12.7 mm (0.5 in.)…”

Section: Figurementioning

confidence: 99%

“…versus 10 such points of 25.4 mm (1 in.) [42]. Still, given that one in every three steps by a subject wearing a standard foot would be expected to contact an unseen obstacle of 1 in.…”

Section: Figurementioning

confidence: 99%

Active dorsiflexing prostheses may reduce trip-related fall risk in people with transtibial amputation

et al. 2014

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Abstract-People with amputation are at increased risk of falling compared with age-matched, nondisabled individuals. This may partly reflect amputation-related changes to minimum toe clearance (MTC) that could increase the incidence of trips and fall risk. This study determined the contribution of an active dorsiflexing prosthesis to MTC. We hypothesized that regardless of speed or incline the active dorsiflexion qualities of the ProprioFoot would significantly increase MTC and decrease the likelihood of tripping. Eight people with transtibial amputation walked on a treadmill with their current foot at two grades and three velocities, then repeated the protocol after 4 wk of accommodation with the ProprioFoot. A mixed-model, repeated-measures analysis of variance was used to compare MTC. Curves representing the likelihood of tripping were derived from the MTC distributions and a multiple regression was used to determine the relative contributions of hip, knee, and ankle angles to MTC. Regardless of condition, MTC was approximately 70% larger with the ProprioFoot (p < 0.001) and the likelihood of tripping was reduced. Regression analysis revealed that MTC with the ProprioFoot was sensitive to all three angles, with sensitivity of hip and ankle being greater. Overall, the ProprioFoot may increase user safety by decreasing the likelihood of tripping and thus the pursuant likelihood of a fall.

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“…In summary, potential obstacles need to be seen approximately 3 m ahead to be negotiated without gait disturbance. 54 An obstacle presenting a 10 mm change in vertical height that lies 3.4 m ahead subtends a visual angle of 8.47 min arc at the observer's eye for an assumed eye height of 1.5 m. We refer to this as the critical size because smaller obstacles are unlikely to lead to a trip, and because larger obstacles should be at least as detectable as is this. The next section discusses the light level desirable to optimise detection of this obstacle.…”

Section: Detection Distancementioning

confidence: 99%

Illuminance required to detect a pavement obstacle of critical size

Fotios

Uttley

2016

Lighting Research & Technology

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This paper investigates the illuminance needed to detect trip hazards for pedestrians walking after dark. In previous work, it was assumed that the critical obstacle height is 25 mm: further review of accident data and foot clearance data suggests instead that 10 mm is the critical height. Eye tracking records suggest a tendency for obstacles to be detected approximately 3.4 m ahead. Interpretation of obstacle detection data suggests horizontal photopic illuminances of up to 0.9 lux are required for peripheral detection of a 10 mm obstacle 3.4 m ahead, according to the scotopic/photopic ratio of the lighting and the age of the observer.

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Sidewalk potential trip points: A method for characterizing walkways

Cited by 18 publications

References 9 publications

Examining the Relationship between Construction Workers’ Visual Attention and Situation Awareness under Fall and Tripping Hazard Conditions: Using Mobile Eye Tracking

Examining the Relationship between Construction Workers’ Visual Attention and Situation Awareness under Fall and Tripping Hazard Conditions: Using Mobile Eye Tracking

Active dorsiflexing prostheses may reduce trip-related fall risk in people with transtibial amputation

Illuminance required to detect a pavement obstacle of critical size

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