Pedestrian Impedance of Turning-Movement Saturation Flow Rates: Comparison of Simulation, Analytical, and Field Observations

TRAF-NETSIM and its successor CORSIM are comprehensive micro-simulation environments that have been widely used to model the urban traffic environment in the United States and abroad. CORSIM is employed in this study to simulate and evaluate the effects of pedestrian flows on right-turn saturation flow rates at signalized intersections. The saturation flow rates returned by CORSIM were compared with field data collected throughout the United States and with three existing analytical models in the United States, Australia, and Canada. These comparisons indicated that CORSIM models pedestrian interference with the turning vehicles more severely than the three analytical methods, but with a smaller effect than the empirical data indicate. Further, the empirical data exhibit a logarithmic relationship between saturation flow rate and opposing pedestrian volume, compared with the linear relationship used in the simulation and analytical models. Implications for the design and analysis of signalized intersections are presented.