基于随机松弛时间的行程时间可靠性计算模型*

提出了基于随机松弛时间的行程时间可靠性动态计算模型。研究了交通系统内部车辆间相互干扰作用对行程时间可靠性的影响。运用交通流动力学理论建立模型,证明了模型的各项异性,并基于蒙特卡洛和欧拉折现法设计相应的求解算法。模型能够较好地反映给定交通供需条件下的行程时间可靠性退化规律,量化交通流内部车辆间相互干扰对行程时间可靠性的影响。算例分析表明车辆间相互干扰程度的加剧会引起行程时间可靠性退化轨迹的明显改变,干扰越剧烈,动态行程时间可靠性的退化速度越快、达到稳定状态时的行程时间可靠性水平越低。拓展了传统行程时间可靠性计算模型仅考虑外部供需的局限性,探讨了交通流松弛时间的随机波动对行程时间可靠性的影响。所建模型和方法可以为高速公路、城市快速路、主干道等大型设施的动态行程时间可靠性预测提供理论依据和实践参考。

Travel time reliability calculation model based on traffic flow dynamics theory considering stochastic relaxation time

This paper proposes a dynamic travel time reliability calculation model considering stochastic relaxation time and studies the influence on travel time reliability by mutual-interference among traffic flows. Traffic flow dynamics theory is used to establish the model which is proved to be anisotropic. Also, the corresponding algorithm is designed based on Euler method and Monte-Carlo simulation. The model can reflect the degradation law of travel time reliability under situation of fixed supply demand, and can quantify the influence on travel time reliability caused by mutual-interference among traffic flows. Example analysis indicates that the increase of mutual interference will cause obvious change in the reliability trajectory. When the interference is more violent, the travel time degradation speed becomes faster and the trajectory reaches lower reliability level. By discussing the influence on travel time reliability by stochastic relaxation time, this research extends the traditional models to considering exterior factors. The model and method established by this research can provide both theoretic basis and practical reference for travel time reliability dynamic prediction of large facilities including highway, expressway and urban arterial roads.