基于元胞自动机模型的C型交织区交通流特性

INVESTIGATION ON TRAFFIC FLOW CHARACTERISTICS AROUND A TYPE C WEAVING SECTION BASED ON CELLULAR AUTOMATON MODEL

根据C型双侧交织区的车辆换道特征建立相应的换道规则,采用多车道元胞自动机模型研究交织区系统的交通流特性.通过数值模拟得到了不同交织区长度下的相图,表明当主路和匝道交通流均为自由流时,交织区长度对系统影响不大,但当主路或匝道拥挤时,交织区长度的增加可以明显改善入口匝道的交通流状况.进一步讨论了主路畅通而交织流量较大情形下主路上的车辆密度、速度和换道频率分布,发现换道集中在合流区和分流区附近,并造成相应路段上的局部拥堵.

The lane-changing rules are proposed on the basis of features of lane-changing behaviours in the two-sided type C weaving section. The multi-lane cellular automata model is adopted to investigate traffic flow in such a weaving section. The phase diagram is obtained by numerical simulation with different weaving lengths. It is shown that the weaving length has negligible effect on traffic states of the weaving section when traffic flows of both main road and on-ramp are free. However, the increase of weaving length can improve the traffic states of on-ramp when the traffic flow of main road or on-ramp is congested. Furthermore, the distributions of density, velocity and lane-changing frequency of vehicles are discussed in the case of free flow of main road and large on-ramp flux. It is found that lane-changing behaviours occur mainly on both merging and diverging areas and lead to local congestion correspondingly.