Time Reliability Analysis Of Urban Road Traffic System

With the continuous improvement of urban traffic demand,the traffic system will be unstable in the period of periodic and aperiodic congestion.Therefore,the reliability of transportation system is paid more and more attention in the performance evaluation of transportation institutions and the communication between institutions and the public.The existing traffic engineering reliability related research mainly focuses on the long-term reliability of daily travel time changes.In this paper,the real-time management of the road and the short-term reliability of the real-time traffic information system are studied.According to the experimental data,the distribution characteristics of the measurement data on the same road are different,but in the past research,the data source of the measurement in the reliability evaluation of the traffic road is generally defaulted to be the same distribution data,such reliability evaluation method may cause some errors to the road reliability evaluation.Therefore,this paper proposes a more effective reliability evaluation index to evaluate the reliability of the road.Simulation experiments show that the reliability index can reflect the internal changes of the road traffic system with a more sensitive degree.Using this index to calculate the reliability can show the internal changes of the road quantitatively in a clear way.At the same time,combining the evaluation index with the commonly used road service level evaluation methods,the road managers or road users can intuitively understand the current or future changes in the service level of the road in a period of time.When identifying the data points of the collected data,this paper analyzes the historical average model and the neural network model with external input by using the measured data,and predicts the confidence interval of travel time reliability.The proposed evaluation method of reliability evaluation index is applied to a small urban OD traffic network simulated by VISSIM simulation software,and the travel time reliability of each road in the network and the reliability evaluation of the whole od network are obtained when the road traffic network is unblocked.When one road in OD traffic network is blocked completely,the travel time reliability of the rest roads and the change of the travel time reliability of the whole OD traffic network are calculated by using the evaluation index adopted in this paper.Through the calculation,the higher the reliability of travel time when there is no traffic accident,the greater the reduction of reliability after the traffic accident.Travel time reliability can quantitatively evaluate and analyze the impact of traffic accidents on roads and OD networks.