On Traffic Data Fusion And Travel Time Prediction Based On Gradient Calibration Method

As a new data-processing technology, data fusion technology and prediction processing have a vast range of prospect for the development and application in the field of transportation. Through the integration and prediction of traffic data, the traffic processed data has a higher accuracy, credibility and is more suitable for traffic control center to handle the traffic situation. Main works is as follows:Firstly, principle of traffic data acquisition technology is introduced, and then the basic theory of traffic data fusion and prediction processing are described.Secondly, by analysis of the model of Artificial Neural Networks, the principle and structure of BP algorithm are discussed in detail. To overcome the drawbacks of slow convergence speed and falling into the local minimum point easily of BP Algorithm, this paper studies an improved BP algorithm called Gradient Calibration method (GC) avoiding increasing algorithm complexity. Then Gradient Calibration method is simulated and studied with the traffic data collected through microwave detectors, which are installed in three consecutive sections at Chaoyangmen area of Beijing. The simulation results demonstrate that gradient calibration could effectively reduce the errors and improve data accuracy in the process of integration.Thirdly, Gradient Calibration method is applied to predict travel time. The error obtained by the Gradient Calibration method is compared with the one by basic BP algorithm. The comparison shows that gradient calibration method is more accurate than basic BP algorithm in prediction of travel time.Finally, an explorative method is made in order to relieve the traffic congestion. Taking the fourth ring road of Beijing as an example, monitoring system would be built on emergency lane of the fourth ring road in Beijing, which will use the traffic data collected by microwave detectors and video cameras. Then the data would be fused for analysis and judgment of the traffic condition. Information Control Center would control the traffic situation with this as a basis. Emergency lane would be open so as to ease the traffic congestion when there is traffic congestion.