O-D Matrix Estimation Methods For Expressway Networks Based On Multi-Source Data

With continuous economic and society development,the process of urban motorization is accelerating and expressway has gradually become the "aorta" of urban traffic.However,as the traffic volume increases rapidly,the load of expressways becomes increasingly saturated,affecting the traffic quality.Due to numerous urban expressway access ramp mouths,nodes connecting urban expressway to other roads become the key to traffic control,so accurate estimation for expressway OD flow so as to implement corresponding traffic management and control measures to improve the city traffic safety and efficiency has important theoretical and practical significance.This paper proposes a data-driven OD estimation method for urban expressway based on multi-source data including video bayonet,mobile phone signaling and floating vehicle track data.First,the network GIS(Geographic Information System)data,AVI(Automatic Vehicle Identification)data,GSM(Global System for Mobile Communications)data and floating car data of multi-source data are discussed mainly from data source,data characteristics,application scenarios and pretreatment method,which provides data support to urban expressway based on multi-source data of OD estimation.Secondly,expressway OD estimation method has been put forward based on video monitoring and mobile phone signal data,with bayonet monitoring road traffic monitoring data of relative error minimum as objective function.The concepts of honeycomb grid and cellpath have been introduced to construct constraints.The path flow estimation problem is transformed into a simple least-squares problem with constraints,the estimated results were evaluated with a specific case and sensitivity analysis was carried out for the influencing factors such as bayonet location and quantity.And then,to further improve the estimation precision of the model,we introduce GPS data to the basic model.Map matching method is adopted for extracting the taxi GPS trajectory identification,to build an OD estimation model of based on "AVI+GSM + GPS" data,and the model has been verified in an example.Finally,part of Shenzhen expressway network is analyzed as a case.The steering ratio of a total of 11 diversion points was obtained by calculating the taxi GPS track data,the empirical study was conducted by combining the traffic monitoring data of 6 video bayonets in the research area with the mobile signaling data of the operator base station.The estimated results verify the bayonet monitoring flow rate for comparison.The deviation of path traffic estimation is within 10%,which proves the rationality and effectiveness of the model.