Studying of Unused Pedestrian Phase Time at Signalized Intersections
Civil and Environmental Engineering
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At signalized intersections, the time length of a pedestrian phase is usually determined based on a relatively low walking speed in order to accommodate most pedestrians (typically 3.5 ft/s). However, in a large number of cases, a part of pedestrian signal phases is not effectively utilized as all pedestrians can finish crossing most of the time before the pedestrian signal phase ends. Consequently, the operational efficiency at intersections would deteriorate with citizen complaints likely generated if the vehicles and pedestrians on other movements are forced to wait whereas the current signal phase serves no pedestrians. In order to improve traffic operations at the urban intersection, it is necessary to study the so-called Unused Pedestrian Phase Time (UPPT). In this research, three factors were identified through the literature review and were selected to develop the UPPT model, which are pedestrian walking speed, pedestrian compliance rate, and pedestrian compliance distribution. A total of 25-hour videos including 1033 pedestrian data samples were collected in Reno, Nevada to analyze pedestrian behaviors. Results indicated that the pedestrian walking speed is influenced by several factors, including pedestrian age, group size, road width, and compliance conditions. Results also showed that pedestrian compliance distribution is significantly different between the first half and late half of pedestrian FDW (Flashing Don’t Walk). Then a model was developed to estimate the UPPT as a function of the three factors. Finally, a case study was conducted to obtain the estimated UPPT at an intersection with long crosswalks.