多模式疏散交通车队配置与车道分配协同优化研究

Collaborative Optimization of Multimodal Evacuation Traffic Fleet Configuration and Lane Allocation

考虑疏散交通的动态性和风险性,研究多模式疏散交通车队配置与车道分配的联合优化问题。首先,根据不同类型车辆的自由流速度,将路网离散为多尺寸元胞网络,采用元胞传输模型模拟混合交通流。然后,以最小化疏散总风险为目标,将多模式交通协同的动态疏散问题描述为混合整数线性规划模型,引入惩罚项消除因模型松弛产生的“车辆滞留”问题。在Nguyen-Dupuis路网中分析不同疏散需求下的最优车队配置、车道分配、疏散效率和疏散路径。结果表明:存在一个疏散交通需求区间,相比单模式疏散,组织多模式车队能够进一步降低疏散总风险,而且最优的公交车配置比例呈阶梯变化;受路网通行能力限制,路网利用率存在上限;疏散总风险指标对疏散需求的变化比网络清空时间更敏感;多模式交通共享的路段一般位于临近风险源的出口通道,大容量的公交车优先占用最短路线,以提升疏散系统的效率。

Considering the dynamics and risk of evacuation traffic,this paper focuses on the joint optimization of fleet configuration and lane allocations for multimodal evacuation traffic.Based on different free-flow speed,the study discretized the road network into multi-size cell network to load multimodal traffic flow via the cell transmission model(CTM).The multimodal traffic cooperative dynamic evacuation problem is formulated as a mixed integer linear programming(MILP)model to minimize the total travel risk of evacuees.The"vehicle holding-back"problem caused by model relaxation is eliminated by adding a penalty item.Numerical experiments are conducted in Nguyen-Dupuis network to analyze fleet configuration,lane allocation,evacuation efficiency,and routes under different evacuation demands.The results show that using multimodal fleet can further reduce the total risk of evacuation compared with single-mode fleet under certain evacuation demand,and the optimal bus proportion changes stepwise against evacuation demand;there is an upper boundary of road network utilization due to the limited road network capacity;the total evacuation risk is more sensitive to the change of evacuation demand than the network clearance time;the exit sections near the risk source are usually shared by multimodal traffic,and allocating the shortest path to high-capacity buses can improve the system efficiency.