Real-time And Online Traffic Flow Prediction Based On Optima Method

Traffic flow forecasting is a key problem of traffic control and traffic guidance systems and it has a significant effect of wisdom and broad application prospects in urban traffic intelligent management and guide residents travel.Urban road traffic flow forecast is mainly based on physical modeling,statistics features and fusion part of intelligent Prediction algorithm to achieve.which can estimate and predict traffic states in future several minutes,but most of them are offline.and to accurately predict of the whole network still exists long distance.and also,unable to make project evaluation and decision support.meanwhile,Important factors that influence results such as the FIFO principle,traffic signal control are always neglected due to inability to introduce and describe.This paper proposed a real-time and on-line traffic flow forecast method based on Optima.First,through the establishment of network models,demand models and initial OD matrix gets real-time road network conditions.because of the difficult in obtaining the OD matrix.based on link traffic flow and turning flow of OD matrix reverse technology obtain the initial OD matrix.The output initial OD matrix is determined by comparing the coincidence degree between the road network distribution flow and the observed flow.According to the traffic flow characteristics of different time periods,a dynamic traffic assignment program is set up,and the travel demand is allocated to the road network to get the network distribution.And then,by building a database model of real-time network information,traffic signal control match the information effectively.Traffic Data Exchanger module、TRE-offline module、TRE-online module help us with the forecast.meanwhile,introduce a trapezoidal model of an adaptation of urban road curve.Considering the existence of the bottleneck of the road,the spillover effect caused by the traffic reverse wave on the upstream intersection is forecasted,and the cumulative flow of the road section is obtained according to the dynamic real-time equalization algorithm.Realize real-time online traffic flow forecast;Finally,the forecast scheme is used to simulate the traffic condition of Wangjing District in Beijing.