Development of alternative methods for delineating diverges in freeway work zones
Greenwood, Aaron Todd
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Work zones are visually and physically complex environments, requiring that drivers maintain control of their vehicle and comprehend atypical and often discontinuous traffic control devices to safely navigate appropriate paths. Freeway diverges represent particularly difficult work zones areas. This thesis investigates current methods of delineating diverges in freeway work zones to determine important characteristics of these methods for future research. A virtual environment was constructed with two ramp geometries: a freeway continuing straight and one curving left. Still images of work zones on these geometries were created using drums spaced 10 ft apart, drums spaced 40 ft apart, drums spaced 40 ± 2 ft apart, and portable concrete barriers. These alternatives were used to construct temporary ramps that were either open or closed. 39 participants were asked to identify whether the ramp was open or closed and their responses were recorded to evaluate the performance of each alternative. Results indicate the importance of the Gestalt principles of closure, proximity, and continuity in perception of temporary exit ramps in work zones. These results will be used to guide future research into methods of delineating diverges in freeway work zones.