在分析随机型用户均衡模型及其优化条件的基础上,充分运用目标函数的一阶、二阶微分信息,从非线性规划理论出发推导出随机型用户均衡模型的敏感度方程。具体推导了均衡状态下路段时间、流量对交通需求、自由旅行时间和路段容量3个输入变量的敏感度方程,并用交通网络要素的选择概率来描述;最后在小型交通网络上,进行了敏感度分析的数值试验。结果表明:敏感度计算可以植入交通网络模型的求解过程,无需增加额外计算工作量,计算方法容易被交通工程师所接受,为研究交通网络的鲁棒性、确定网络的关键要素等提供了有效的解析方法。
On the basis of analyzing stochastic user equilibrium model and its optimal conditions, applying the first order and the second order informations, sensitivity equation of stochastic user equilibrium model was deduced by nonlinear planning theory. Sensitivity equations about relation between link time, link flow and traffic demand, free travel time and link capacity under equilibrium state were deduced. Selectivity probability of traffic network was used to describe the sensitivity equation. The numerical example was executed on a small traffic network. Results show that sensitivity can be implemented in the procedure of solving the traffic network model, the sensitivity analysis does not require any additional calculation and provides a useful tool for analyzing the robustness or determining the critical element of the traffic network.