考虑脆弱性的离散交通网络设计

针对交通网络中的脆弱单位进行优化是保证路网稳定运行的前提。为此，选择改进后能从多方面综合反映路网脆弱性的评价指标，分析了脆弱性指标和路段数、交通量之间的关系，并利用双层规划模型来描述考虑脆弱性的离散交通网络设计，其中上层模型以路网脆弱度最小化为优化目标，下层模型为用户均衡配流模型，通过设计遗传算法并结合Frank-Wolfe算法进行求解。算例结果表明，投资金额为300万元时，与以单一路段脆弱性为优化目标的方案相比，从路网整体角度出发提出的优化方案可将13条路段的脆弱度降低到理想值，而前者只有仅仅7条，并且此时该方案可将路网脆弱度降低38.5%，相比于前者多降低9.1%；分析还发现在OD（Origin-Destination,起讫点）需求越大的情况下，需投入更多的建设资金才能将路网脆弱度降低到理想值。

Discrete transportation network design considering vulnerability

Optimizing the vulnerable units in the traffic network is the premise to ensure the stable operation of the road network. Therefore, the improved evaluation index which can comprehensively reflect the vulnerability of road network from many aspects is selected, the relationship between the vulnerability index and the number of road sections and traffic volume is analyzed, and the bilevel programming model is used to describe the discrete traffic network design considering vulnerability. The upper model takes the minimization of road network vulnerability as the optimization goal, and the lower model is the user equilibrium distribution model, By designing genetic algorithm and combining Frank Wolfe algorithm. The example results show that when the investment amount is 3 million yuan, compared with the scheme taking the vulnerability of a single road section as the optimization objective, the optimization scheme proposed from the perspective of the whole road network can reduce the vulnerability of 13 road sections to the ideal value, while the former is only 7. At this time, the scheme can reduce the vulnerability of the road network by 38.5%, which is 9.1% more than the former; It is also found that the greater the OD(Origin-Destination) demand, the more construction funds need to be invested to reduce the road network vulnerability to the ideal value.