Traffic Dynamics Around Weaving Section with Mixed Slow and Fast Vehicles based on Cellular Automata Model

The traffic dynamics are very complex around the weaving section, which is a typical and primary bottleneck on urban expressway. Many simulation models have been established to investigate the dynamics and the operational capacity around the weaving section. However, those models mainly focus on the homogeneous condition, which is different from the real traffic condition. In fact, there are many slow vehicles, such as buses or trucks, with larger size and slower velocity. The mutual interference among different types of vehicles leads to much slower operational capacity comparison with that under homogeneous condition. This paper takes into account mixed traffic condition including small fast and large slow vehicles. The two kinds of vehicles are different in the maximum velocity and vehicle length. A cellular automata model is proposed to simulate the dynamics around the weaving section. Then the traffic dynamics and the operational capacity of weaving section are investigated by analyzing simulation results. The influencing factors considered in the simulation include the proportion of large slow vehicle, and the inflow rate of weaving vehicle. The simulation results show that, the larger the proportion of large slow vehicle, the lower the operational capacity. And the traffic flow fluctuates stochastically with larger proportion of large slow vehicle. Such results are meaningful to understand the traffic flow evolution mechanism around weaving section and helpful to design the traffic control methods.