Modeling Capacity of Shared Right-Turn Lanes at Signalized Intersections Considering the Lag Green Time of Right-Turns

Turning vehicles often play an important part at signalized intersections owing to the conflicting movement of different traffic. In the real-world, the through movement of shared lanes is probably blocked by the right-turn movement because of the lag time. In this situation, the green time of shared lanes cannot be fully used. Meanwhile, the signal control of right-turn lag time is utilized in large quantities. In this paper, a mathematical model is presented according to the probability and combinatory theory. The capacity model was proposed to exactly calculate the blockage probability of right-turn movement caused by the lag time and the capacity of single-shared lanes at signalized intersections. The proposed model was verified by using microscopic traffic simulation software VISSIM. The results show that the simulated results were consistent with the theoretical model.