Research On The Effect Of Speed Discrete On Traffic Efficiency Of Freeway

In recent years, along with the social economic development, transportation business of booming development, highway construction get rapid development, and plays a more and more important role in social economic activities. To the highway transport ability people put forward more and more highly demand, not only from the capacity to increase, the concept of traffic efficiency also raised by some scholars gradually. At the same time as a result of road conditions, the vehicle condition and so on the different conditions caused by the highway basic sections speed discrete makes road traffic efficiency discount greatly, due to the lack of the influence mechanism research between speed discreteness and basic sections traffic efficiency, form the point of how to control the speed discrete to optimize traffic efficiency and the optimization method research is still in its beginning stages. In this paper, relying on the National Natural Science Foundation of highway speed discrete characteristics, from the measured data, Study analysis of the affect relations between speed discrete and traffic efficiency and the impact mechanism. Through the establishment of a microscopic traffic flow dynamics model, Simulation of the traffic flow under different lane management measures.Firstly, through the actual survey data, analysis and study section of the general characteristics of speed discrete and the relationship between the traffic efficiency and speed of discreteness, through the actual data show the significance of efficiency traffic in the traffic engineering, and distinguish between capacity, the methods which to get the traffic efficiency are illustrated, analysis the influence of the accelerate and deceleration of the vehicles to traffic efficiency.Secondly, research on the Impact conditions and impact mechanism between speed discrete and traffic efficiency, analysis the influencing factors of speed dispersion of basic sections under different traffic flow states, and to explain the impact of vehicles on the road section traffic efficiency in the accelerate and deceleration state from microscopic. The model parameters are calibrated by using the model parameters of individual difference and genetic algorithm. The model parameters are calibrated and the model parameters are compared with the actual traffic flow data. The results show that the acceleration of the target vehicle in the following process is influenced by the first one, which is more than the influence of the second vehicles in front. In the target lane choice and gap acceptance stage, in front of the first car distance and in front of the second car car speed on the target vehicle acceleration effect accounts for the proportion of large, lane changing process execution, the target vehicle by the driveway to the front of the vehicle and the target lane in front of the vehicle impact, the partial angular velocity depending on the lateral displacement.Thirdly, in the existing with the following model and changing model based on the proposed improved FVD following model and lane changing lanes utility-based model, built multi-lane traffic flow dynamics model based on the two vehicles and lane changing rules. Model by the program and applications reflect individual differences in the model parameters discretization method, the parameters of the model calibration, the data obtained by numerical simulation of the model with the actual traffic flow survey data comparison, and to verify the real availability of the model.Finally, based on the microscopic traffic flow dynamics model, the numerical simulation of the actual operation of the basic freeway different lane speed limit management rules, the basic sections of different density traffic flow simulation, test of basic sections speed dispersion and the impact of the sections of traffic efficiency. Compare different lane speed limit management mode based on the results of the numerical simulation analysis, the impact on the basic sections passage efficiency, and asked the lane management methods to reduce the speed discrete and improve the efficiency of the basic sections passage. The results show that the proportion of large vehicles and small cars is relatively balanced, the traffic flow is more uniform, and the speed limit measures of group III are more important, and the traffic flow can reach steady state. For traffic flow models, speed, etc., the proportion of traffic flow in a day, the characteristics of traffic flow in a large change, the use of group IV is better, can make the road to play a greater effectiveness, but the traffic flow to reach the steady state for a long time. The number of lane change will affect the passage efficiency, the more the number of the other road, the greater the speed of the road, which makes the road traffic efficiency is lower.