中文摘要：

利用多车道元胞自动机模型研究双下匝道系统的交通流动态演化特征．采用可变情报板来实现交通诱导，着重分析驾驶员选择目标匝道的决策行为及其对道路通行能力的影响．分别建立了无可变情报板的基本模型和有可变情报板的诱导模型．通过数值模拟，分别给出了相应的相图、道路通行能力、流量图和时空斑图，分析了进车概率、出车比例和出车道长度对交通行为的影响．通过对两个模型模拟结果的比较分析，发现当出车道长度较小而进车概率、出车比例都较大时，可变情报板的诱导信息能明显提高下游匝道的利用率，改善道路交通流状况，从而缓解交通拥堵．

英文摘要：

In this paper, a multi-lane cellular automata model is adopted to investigate the evolution of traffic flow in a two-off-ramp system. The variable message sign （VMS） is used to realize traffic flow guidance. More attention is paid to the decision-making behaviors of the driver, i.e., choosing the target off-ramp and its influence on road capacity. The original model without VMS and the improved model with VMS are proposed respectively. Through numerical simulation, the corresponding phase diagram, the capacity, the flux of each section and typical patterns are obtained, then the effects of the injection probabilities, the fraction of leaving vehicles and the length of the exit lane on capacity are analyzed in detail. When the length of the exit lane is rather short but the entering probability and the fraction of leaving vehicles are rather large, the road capacity is increased noticeably with the help of VMS and therefore the state of traffic flow is improved. It is shown that the utilization efficiency of downstream off-ramp is enhanced and traffic jams are alleviated due to the guidance of VMS.