Influence of Pedestrian Traffic on Capacity of Right-Turning Movements at Signalized Intersections

Pedestrians have a significant influence on vehicle capacities of turning movements at signalized intersections. The increasing emphasis on pedestrian traffic has highlighted deficiencies in the relevant research in China. It is imperative to quantify accurately the effect of pedestrians on vehicle capacity to provide a basis for traffic operations and facility designs in mixed traffic conditions. This study proposes an analytical model for the capacity of right-turning movements influenced by pedestrians at signalized intersections. The model takes into account pedestrian behavior, pedestrian–vehicle conflict mechanisms, and pedestrian arrivals in platoons. The conflict-zone capacity is modeled on the basis of the conflict mechanism. The model was calibrated and used as the basis to calculate right-turn vehicle capacities. The capacities yielded by the proposed model depend strongly on the average conflict times. The results show that pedestrians have a strong impact on the right-turn capacities at low pedestrian volumes and that the effects of additional pedestrians decrease as the pedestrian volumes increase. VISSIM was employed to simulate the interactions between right turns and pedestrians to validate the model. A numerical example is presented to compare the proposed model with the simulations and several existing analytical models. At low pedestrian volumes, the predictions of the other methods are approximately equal; at high pedestrian volumes, the models assuming pedestrian priority yield lower capacities than those assuming no priority.