用紧急-缓和类交通流模型探索旅行时间的道路状况效应

关注环境与输运系统的相互作用，探索旅行时间的道路状况效应，需要流体力学、输运科学、应用数学等学科的知识融合。这些道路状况效应涉及到：道路隧道的车速上限、隧道长度；道路上、下坡的斜率和长度；匝道交叉口的出、入口车流量；不同路段的宏观基本图形状变化等。拟用非牛顿流体的本构关系，通过流动比拟发展急、缓两类交通流模型，把刹车距离、自由流速度、二次临界速度作为交通基本图的参数. 建立交通流计算平台，模拟交通流动态，从而计算出旅行时间。拟收集、整理交通流实时观测数据，制成图、表, 对发展的交通流模型和旅行时间预测方法进行检验, 挖掘模型的应用潜力。本项目的关键，在于合理融合流体力学、应用数学、输运科学知识。本项目的成果，对交通控制、管理的优化, 交通信息系统性能的改善，有重大意义。

To focus on the interaction between environment and transport system, exploring road condition effects of travel time requires the knowledge fusion of fluid mechanics, transport science, applied mathematics and other disciplines. The road condition effects involve: the upper limit of vehicular speed of road tunnel, the tunnel length; the slopes and lengths of the road uphill and downhill segments; the on/off ramp flows at the ramp intersections; the shape change of the macroscopic fundamental diagram (MFD) of different road segment. The constitutive relationship of non-Newtonian fluid is used to develop urgent-gentle class traffic flow model, which takes braking distance, free flow speed and secondary critical speed as the parameters of the MFD. A calculation platform of traffic flow is to be established for simulating traffic flow dynamics, which can be used to predict the travel time. It is expected to collect and organize real-time observation data of traffic flow for making figures and tables to test the traffic flow model and prediction method of travel time. The key to this project is to rationally integrate knowledge of fluid mechanics, applied mathematics, and transport science. The results of this project are significant for the optimization of traffic control and management as well as the improvement of traffic information system performance.