Saturation flow rate estimation under rainy weather conditions for on-line traffic control purpose
The capacity or saturation flow rate of an urban street intersection is defined by physical factors of the roadway, traffic factors, and environmental disturbances. Roadway is fixed by design and construction its physical characteristics exert a constant influence on intersection capacity. Traffic factors have various effects on capacity, but they are also subject to control and regulation to a great degree. Environmental factors cannot be controlled, and thus their effect can be compensated for only by preparation in advance of occurrence. Rain, the most common environmental disturbance to the saturation flow rate that is a base value for capacity, was studied in this research. Rainfall information for September 1997 in Seoul Metropolitan area was correlated with traffic data records at urban intersections to obtain data indicating the effect of rain on prevailing saturation flow rates. Rain was found to reduce the saturation flow rate of intersection to between 87 and 96 percent of the dry weather flow rate. The study also recommends possible revisions in the saturation flow rate estimation algorithm being tested for future deployment of the “New Signal Control Systems”.
KeywordsWeather saturation flow rate signalized intersection rain control
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