Effects of right-turn vehicles on traffic flow

In real traffic, the right-turn vehicles at intersections are not controlled by signal lights and their effects are neglected. In this paper, we develop a cellular automaton model to formulate the complicated turning behaviors of vehicles at intersections. Simulation results are quite in accord with the observation on the Beijing's 4th ring road. It is found that the right-turn vehicles may produce queue near the intersection, a short lane designed for right-turn has prominent effect in improving traffic flow, but, a too long lane for right-turn cannot further decrease the stop ratio as expected. These findings deepen our understanding on the effects of right-turn vehicles and may help the design and management of intersections.