基于地面路网MFD 的快速路出口匝道流量分配模型

过于集中的流量分配易导致出口匝道和与之相衔接的地面道路过饱和，进而影响快速路和地面路网的通行效率.为提高路网中车辆通过快速路到达目的地的通行效率，基于地面路网宏观基本图（Macroscopic Fundamental Diagram，MFD），以出口匝道通行能力和与之相衔接的地面路网承载能力为约束条件，以整个路网的车辆总行程时间最短为优化目标，建立快速路出口匝道流量分配模型.根据宏观网络车流平衡方程，采用改进的遗传算法对模型进行求解.最后，通过实际路网验证了模型的有效性.结果表明，该模型可有效提高车辆通过快速路到达目的地的通行效率，同时降低出行成本.

Assignment Model of Freeway Off-ramp Flow Based on MFD of Ground Network

Over-centralized distribution of flow is easy to lead to the ground road and the off-ramps being over- saturated, and affect the travel efficiency of the mainstream and the ground network. To improve the traffic efficiency of the vehicles arriving at destinations through the freeway, the flow assignment model of off-ramp, based on the macroscopic fundamental diagram (MFD) of the ground network, is established with the shortest total travel time of vehicles in the entire road network as the optimization goal. It is with the traffic capacity of off- ramp and the ground network connected with off- ramp as constraint. Furthermore, according to the equilibrium equations of the traffic flow of the macro network, the model is solved by an improved genetic algorithm. Finally, the validity of model is verified by an actual network. The research results show that the model can effectively improve the traffic efficiency of vehicles through the expressway to the destination and reduce the cost of travel.