Study on Traffic Flow at On-ramp Junctions in Urban Freeway with Cellular Automaton Model

Numerical simulation was applied to study on-ramp junctions area traffic flow characteristics using one-dimensional cellular automaton (CA) model, which based on analyzing the traffic flow action characteristics. In course of study, we constructed some reasonable lane-changing rules to analyze the special traffic flow characteristics, affected by parameters of traffic volume and inflow rate, which based on setting up. The results showed that there was a slight disturbance with the inflow to mainline flow at the moment of little probability of the inflow. However, with the inflow probability increasing, the mainline flow would be suffered from a serious disturbance. Especially, traffic jam could be produced when the mainline and on-ramp volumes increasing to a certain level. But for the outflow, the cases are completely different, mainline exit section will be at the phase of saturation when the inflow probability exceeding 0.5. The results can provide some references for managing the on-ramp junction traffic system.