Study On Short - Term Traffic Flow Forecast And Warning Of Expressway

From the spirit we can see that the early warning management mechanism of highway is imperative. The forecasting and warning as a joint management mode can monitor and precontrol various state of progress in development which make the the development trend of progress closer to the will of the people. On the combination of the traffic prediction and early warning phase point of view, the paper proposed early warning processing of traffic safety in expressway due to flow problems.Although in terms of long-term observation, highway traffic flow is high uncertainty and time-varying. But it has strong stability and chaotic characteristics in a short period of time, We only use the traffic flow as a time series for short-term traffic flow prediction. To make use of the limited experimental data to construct a new attractor to study the dynamic behavior of the system, it is necessary to phase space reconstruction. Therefore, this article selects the chaos forecasting model for short-term traffic flow prediction. First of all, use C-C algorithm to calculate the parameters needed to reconstruct phase space, the embedding dimension and delay time. Then, calculate the lyapunov index what is used to determine characteristics of chaos time series by using the collected traffic flow time series in phase space reconstruction. When conformed to the chaotic characteristic, utilizes the maximum lyapunov index prediction model for short-time traffic flow forecasting. Finally, with the actual of traffic on the road as a time series, make chaotic forecasting models to by the use of the modeling and simulation. Then, contrast reserved real value and predictive value for the sake of error analysis. Results show that the prediction effect is better.After we predict short-term traffic flow, we finish the foundation work of the traffic safety warning problem for Freeway traffic flow. And we accord to the prediction traffic flow to simulate traffic flow of the experimental section by Paramics microscopic simulation software. Next we can get the prediction traffic flow by data analysis tool. Then according to the analysis of early warning theory and the method of interval alarm limit to carry on the early warning analysis for The experiment road traffic safety, and contrast and evaluate with the actual road conditions. Results show that, the early warning method is feasible.