城市交通拥塞辐射模型及其对路网服务能力损伤研究

为预防和治理城市路网系统中交通拥塞的辐射扩散以及由此造成的路网系统服务能力损伤,从新的视角对交通拥塞辐射扩散规律进行研究。将毒气在有限空间内的泄漏扩散抽象为交通拥塞的辐射蔓延,首先运用Python软件对高德地图API的WEB服务进行实时路况数据爬取,并对爬取的数据、浮动车数据、SCATS监测的流量数据以及其他交通信息数据进行预处理。在此基础上建立基于高斯烟雨模型的城市道路拥塞辐射时空模型并且充分考虑邻居节点和路段的交通运行状态以及不同道路等级对拥塞传播范围的影响。对模型调节参数U进行标定,得出快速路、主干路U值均为1,次干路U值为0.7。然后通过实例进行验证,结合实际值将模型计算结果与高德地图预测值进行比较,所建立模型的拥塞最大辐射边界、拥塞辐射时间预测精度要更准确,整个拥塞过程模型拟合度较高,模型适用性强。最后在城市道路拥塞辐射时空模型的基础上利用材料力学中切应力对材料的损伤原理,以拥塞某传播方向为研究对象,计算出拥塞辐射传播给路网中的某路段造成的通行能力失效值。分析路网中路段通行能力下降对路网服务能力的损伤影响,进而给出路段重要性识别方法。研究成果可为交通管理部门加强关键路段治理以及制定缓堵政策提供参考。

Urban Traffic Congestion Radiation Model and Damage Caused to Service Capacity of Road Network

To prevent and control the spread of traffic congestion in the urban road network system and the consequent damage to the service capacity of the road network system, the policies governing the spreading traffic congestion were studied from a new perspective. This paper abstracted the spread of toxic gas in a limited space and was considered to be analogous to the spread of traffic congestion. Initially, real-time traffic data through a web crawling service of the high-tech map API was carried out using Python; subsequently, the crawling data, floating car data, traffic data monitored by SCATS, and additional relevant traffic information, were preprocessed. Considering the influence of traffic status of the neighbor nodes, road sections, and different levels of road, on the congestion transmission range, the space-time model of urban road congestion radiation based on the Cloud model was established. The model adjustment parameter U was calibrated, and it was observed that U values of the express and the main trunk roads were obtained as 1 compared to the U values of secondary trunk roads, which were obtained as 0.7. Subsequently, the results of the model calculation were compared with the actual values and the predicted values based on high-tech map for verification using the sample in the study. The model used in the study exhibits positive attributes, including maximum radiation boundary and higher prediction accuracy of congestion radiation time, strong applicability, and high compliance to the entire congestion process. Finally, based on the space-time model of urban road congestion radiation, using the principle of shear stress damage caused to materials in material mechanics, and taking a particular direction of congestion as the research objective, the failure value of traffic capacity is calculated, which is caused by congestion radiation transmission to a section of the road network. Analysis of the damage impact on capacity decline of road network service capability, and further to provide identification method for the importance of the road segment. This study can serve as a reference model for traffic management departments to strengthen the management of key road sections and formulate congestion mitigation policies.