Research On Urban Traffic Overflow Prevention And Control Strategy

Nowadays,with the rapid development of economy,the promoting effect of traffic on economy is self-evident.Nevertheless,with the increase of automobile inventory,the present road resources can no longer meet the growing traffic demand.Several problems arise,such as traffic jam,accident proneness and environmental pollution,which have severely impeded the economic development.In recent years,the problem of traffic jam is on the increase and the traffic overflow phenomenon also occur from time to time.The traffic overflow phenomenon refers that under the restriction of downstream intersection,upstream vehicles overflow from intersection and directly cause the intersection impassable.Traffic overflow is a form of road traffic oversaturation and without control,it will spread with high-speed from one intersection to several intersections and even to the whole road network,which will eventually cause the traffic network paralysis.In this paper,firstly,we conduct research on transmission mechanism of traffic overflow based on the traffic flow theory and then establish a vehicle queuing prediction model based on the parking wave velocity which lays the foundation for the determination of traffic overflow range.At the same time,the properties of traffic zone have also been discussed in this paper.We take advantage of the basic theory of the macro map of traffic zone to determine the optimal vehicle number in a traffic zone at first and then keep the vehicle number in a divided traffic zone at a reasonable level by using the boundary control strategy of feedback gate control,thus making the traffic flow within the zone achieve optimal and preventing the occurrence of traffic congestion.What's more,the VISSIM simulation software is also applied in this paper to verify the rationality of the control strategy by simulation.For the traffic overflow caused by traffic accidents,according to the different stages of traffic accident treatment process,different control measures are taken in this paper.The control of traffic overflow generally follows the principle of "internal evacuation and external induction".We combine the traffic control and traffic induction together to form a feedback mechanism.For internal area,we adopt the feedback gate control strategy and take the number of vehicles flowing into and out of the overflow area as the control object.Restricting the entry of external vehicles and making regional vehicles drive away from overflow area as soon as possible can reduce the total number of vehicles in the area and realize the dissipation of internal overflow.Meanwhile,closure is carried out on the periphery to prevent vehicles unknowingly flooding into the overflow area and aggravating the traffic overflow.For the closured vehicles on the periphery,a vehicle path selection method under the condition of traffic overflow is proposed in this paper.For on and off control measures under the traffic overflow condition,the method provides travelers with reasonable guiding driving information.It can not only decrease the loss of travelers from the traffic overflow but also effectively control the traffic overflow from further diffusion.Based on studies above,a set of urban traffic overflow prevention and control system is developed in this paper.The system realizes the visual expression of visual display,preventive measures and control strategies of traffic overflow.The system also helps to improve traffic managers' understanding of traffic overflow hazards and provide scientific and reasonable guidance for the solution of traffic overflow.To summarize,this paper conducts the in-depth analysis of traffic overflow phenomenon,establishes the diffusion model of traffic overflow and puts forward corresponding preventive measures to reduce the occurrence of traffic overflow.Meanwhile,reasonable control strategies and inducing measures in traffic overflow condition are also proposed in this paper.The control strategy adopted in this paper lays the foundation for the follow-up research in this field.