Biomedical subjects

J K Caird

Publications and source records attributed to J K Caird.

4 recordsLinked to original sources

PubMed2004

The relationships between organizational and individual variables to on-the-job driver accidents and accident-free kilometres.

Highway fatalities are the leading cause of fatal work injuries in the US, accounting for approximately 1 in 4 of the 5900 job-related deaths during 2001. The present study focused on the contribution of organizational factors and driver behaviours to on-the-job driving accidents in a large Western Canadian corporation. A structural equation modelling (SEM) approach was used which allows researchers to test a complex set of relationships within a global theoretical framework. A number of scales were used to assess organizational support, driver errors, and driver behaviours. The sample of professional drivers that participated allowed the recording of on-the-job accidents and accident-free kilometres from their personnel files. The pattern of relationships in the fitted model, after controlling for exposure and social desirability, provides insight into the role of organizational support, planning, environment adaptations, fatigue, speed, errors and moving citations to on-the-job accidents and accident-free kilometres. For example, organizational support affected the capacity to plan. Time to plan work-related driving was found to predict accidents, fatigue and adaptations to the environment. Other interesting model paths, SEM limitations, future research and recommendations are elaborated.

Accidents, Occupational↗

PubMed2001

Visual search for traffic signs: the effects of clutter, luminance, and aging.

Latency and eye movement measures were used to examine the effects of aging, clutter, and luminance on visual search for traffic signs embedded in digitized images of driving scenes. Initially 14 older and 14 younger observers classified daytime and nighttime traffic scenes as containing low or high amounts of clutter. Next, an independent sample of 14 younger and 14 older participants searched for traffic signs contained within these scenes. Errors were more common among the elderly. Search efficiency declined with increased clutter and with aging. However, relative to the young, older adults did not suffer disproportionately as a result of increased clutter. The methods developed might be profitably employed to assess sign conspicuity and sign acquisition during driving.

Accidents, Traffic↗

PubMed1995

Performance, workload, and fatigue changes associated with automation.

The experiments discussed in this article addressed the influence of part-task automation on operator performance, workload, and fatigue in a multitask environment. The overall task environment included tracking, resource management, and multiple monitoring subtasks. Slower, more accurate monitoring and better resource management were observed when the tracking subtask was automated. Although lower workload was reported when tracking was automated, fatigue increased equally during periods of manual and automatic tracking. When participants could control workload by shifting between manual and automatic tracking, participants with 7 hr of training switched between automatic and manual tracking. Their performance during optional automation periods was superior to their performance in conditions in which only manual control or only automated control was available. The findings argue for the utility of discretionary control of automated systems.

Adult↗

PubMed1993

Experimental evaluation of a model of mental workload.

This study was designed to test predictions from a model of mental workload. The model predicts that mental workload grows as perceived distance from a task goal increases and the effective time for action decreases. Decreases in workload can be achieved by actions that bring the task goal into the region of acceptable time/distance constraints for successful resolution. We reported an experiment that tested these assertions using the Timepools performance task. Timepools generates a spatial representation of a shrinking temporal target to assess the effects of path length (i.e., the number of sequential targets to be acquired) and shrink rate (i.e., elapsed time during which the circle is halved in area) on reaction time (RT), movement time (MT), error rate, and the subjective perception of workload. Data from the experiment indicated systematic effects for task-related factors across performance and workload measures. Path length and shrink rate had differential effects on both RT and MT, which were also reflected in the components of the individual workload scales. The results support a general form of the workload model which may help researchers and practitioners in the difficult task of workload prediction.

Adult↗