Modeling And Analyzing Urban Road Traffic Systems Around The Bus Stop

Traffic bottleneck plays an important role in urban traffic systems, which is usually involved with most traffic congestions and other complex non-linear traffic phenomena. Bus stop is one of the most typical bottlenecks on urban highways and other roads. In china, bus stop is often close to an on- or off-ramp on urban highways, thus various vehicles will inevitably interweave together when passing through. On some other roads, bus stop is usually set straightly on the non-motorized lanes, causing traffic interferences between motorized vehicles and non-motorized vehicles. In this work, traffic system around bus stop is modeled based on traffic dynamic models, and the traffic characteristics near bus stop is analyzed. The main contents are given as follows:1. Based on a two-lane cellular automaton model, the combined bottleneck of the on- or off-ramp and its nearby bus stop is modeled. The flux, capacity, and the spatial-temporal evolution features are analyzed. The results suggest that the bus stop should be set upstream the on-ramp, and downstream the off-ramp to enhance the road capacity and the utilizing efficiency. Moreover, the comparison between the above two optimal cases shows that the on-ramp has weak effects on the upstream flux of the main road, while the off-ramp can greatly influence the upstream flux of the main road and its fluctuation.2. Based on the velocity-dependent-randomization cellular automaton model and BCA multi-value cellular automaton model, the mixed traffic system near bus stop is modeled to reflect traffic traction between motorized and non-motorized vehicles under periodic boundary conditions. Some macroscopic features including flux, average velocity, and travel time, with respect to motorized and non-motorized vehicle occupancy are discussed. Based on these discussions, the velocity-occupancy relationship under mixed traffic of motorized and non-motorized vehicles is proposed, and the results obtained by the proposed function fit well those simulation results.3. Based on a class of hybrid macro-micro simulation scheme, the traffic flow disturbed by non-motorized vehicles around a bus stop is modeled. The road is divided into micro-link and macro-link. In the micro-link where the bus stop is located, a car following model is used, and the disturbance of non-motorized vehicles is introduced. In macro-links, the LWR continuum model is applied. The results show that the hybrid model can well reproduce the evolution features of traffic congestion under differentsituations.