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.