Identification of Factors that May Affect the Discharge Flow at a Bottleneck

This study investigates various factors that cause the reduction of discharge flow at a bottleneck on an urban expressway. The current worst bottleneck on Tokyo Metropolitan Expressway Network seems to be combined complicate factors that affect the discharge flow at the bottleneck. Five causing factors, merging ratio, longitudinal gradient, duration time involved in congestion, environment of backlight and brightness are considered, and the impact of these five causing factors are investigated. Then the results supported the hypothesis that all of the five causing factors affect the discharge flow rate.