Prediction of freeway traffic incident delay based on simulation

In order to study the influence of different vehicles to incident delay, traffic simulation is applied to make the delay predictions. Three major parts, respectively the establishment of simulation platform and parameter calibration, survey and calculation of traffic data, and case study, are described in the paper. For the establishment of simulation platform and parameter calibration, at first, the local parameter and the global parameter, which need to be calibrated while making the delay simulation, are chosen. Then, the performance evaluation index and the performance evaluation target are proposed and the minimum simulation times are determined based on the statistical analysis. Finally, the flow of parameter calibration is designed, which first calibrates the local parameter and then calibrates the global parameter. For the survey and calculation of traffic data, at first, based on the toll data, the calculation method of the vehicle data, the evaluation index data and the incident delay data, are proposed. Then, these data are taken as the true values to calibrate the parameters and validate the simulation delay. At the same time, the incident duration is predicted. For case study, this paper takes six traffic incidents which took place in link 170002 of Nanjing-Nantong freeway (hereinafter as Ning-Tong freeway) in 2010 as sample data to calibrate the parameters and simulate the delay, and further compares the simulation delay with the true delay. The simulation results indicate that the calibrated model is consistent with the real link, the calculation of incident delay based on the simulation is more suitable and accurate, and this delay prediction is convenient to assist the freeway operators to make strategic decisions for the incident management.