交叉口与公交站组合配置下的交通流模拟研究

Traffic Flow Simulationin of a Scenario with Signalized Intersection and Bus Stop

在道路系统中,交叉口和公交停靠站附近常出现局部交通堵塞,是干扰城市交通畅通的主要瓶颈.考虑交叉口和公交停靠站的组合配置情景,基于元胞自动机模型,在开放边界条件下对双车道混合交通流的车辆换道和停靠行为进行细化,模拟研究需求变化和公交比例对整个交通系统的影响.仿真结果表明,对于不同的公交车比例,存在一个临界流入率,该临界值随着公交车比例的增加而逐渐降低.在临界值以内,车流属于自由流,流量随着流入率的增大而升高,而在临界值以外,流量达到饱和状态,不再随流入率增大而升高.在交通高峰期,信号交叉口上游排队会影响公交停靠站附近车辆运行.因此,根据交通需求设立合适的车站位置和信号灯周期是非常必要的.

In the real road traffic system, local congestion always occurs near the intersections or bus stops, which have become the main bottlenecks of urban traffic development. Considering the scenario with signalized intersection and a near-by bus stop, this paper investigates the lane-changing and dwelling behaviors in a two-lane mixed traffic and conducted the simulation using a cellular automaton model under open boundary condition. Simulation results show that for different proportions of bus flow over the whole flow, a critical probability sending vehicles into the system exists and represents the decreasing trend with respect to the bus flow proportion. Within the critical value, traffic is always the free flow and the flow increases with the probability; whereas, beyond the critical value, the traffic will be saturated. The paper proposes that during rush hours, the queuing upstream the intersection can stretch to the bus stop and then disturb the normal dwelling operation of buses. Therefore, it is necessary to reasonably design the position of signalized intersection and the corresponding cycle time.