David R. Ragland

Learn More
The authors used observational job analysis as a conceptually based technique to measure stress factors unbiased by worker appraisal with 81 transit driving tasks on 27 transit lines. Stressor dimensions included work barriers that interfere with task performance due to poor technical-organizational design, time pressure, time binding (autonomy over time(More)
Eighty-one observational work analyses were conducted to measure stressors independently of worker appraisal in the San Francisco transit system. On the basis of action regulation theory, stress factors were defined as hindrances for task performance due to poor work organization or technological design. Stressors included (a) work barriers, defined as(More)
Urban transit operators' medical symptoms and conditions exceed other occupational groups, resulting partly from working conditions. Medical outcomes among operators have an impact on the transit system, including on performance, work attendance, and medical costs. This is exacerbated by external economic and political pressures in which expected service(More)
The market segmentation analysis for bicycle commuting can help identify distinct bicycle market segments and develop specific policies or strategies for increasing the bicycle usage in each segment. This study aims to use the approach of attitudinal market segmentation for identifying the potential markets of bicycle commuting. To achieve the research(More)
OBJECTIVES This report examines the role of (a) disease processes affecting vision, (b) reported troubles with vision, (c) physical symptoms affecting the eyes, and (d) objective measures in reported driving limitation due to problems with eyesight among older drivers. METHODS Data for this study (N = 1,840) were obtained from participants in a(More)
BACKGROUND Collision geocoding is the process of assigning geographic descriptors, usually latitude and longitude coordinates, to a traffic collision record. On California police reports, relative collision location is recorded using a highway postmile marker or a street intersection. The objective of this study was to create a geocoded database of all(More)
OBJECTIVE Research findings suggest that, in addition to hostility, social dominance-related variables may be related to morbidity and mortality. The purposes of the present study were to evaluate a) whether pressured social dominance (defined as a pattern of structured-interview-defined characteristics of verbal competition, immediateness of response, and(More)
BACKGROUND Musculoskeletal injuries are a common cause of morbidity after road traffic injury (RTI) in motorizing countries. District hospitals provide front-line orthopedic care in Uganda and other sub-Saharan African nations. Improving care at the district hospital level is an important component of the World Health Organization's strategy for surgical(More)
Rear-end collisions would occur if vehicle speeds decrease abruptly when encountering kinematic waves (KWs) emanating from active bottlenecks. This study aims to develop a control strategy in variable speed limits (VSL) to reduce rear-end collision risks near recurrent bottlenecks. Using the crash prediction model developed for rear-end collisions related(More)