The Application of The Double Queue Asymmetric Gated Service Polling Control Theory in Intelligent Traffic System

paper presents a new use of double queues asymmetric gated service polling system in the intelligent traffic light control system.Usually there are more vehicles in main road than minor road,so there are more green light time be needed in the main road.From the computer simulation and theory analysis,we can find that the application of double queues asymmetric gated service polling theory in intelligent traffic system can balance intersections load and set suitable passing time for vehicles to assure the roads open.


Introduce
Withing the development of urban economy, the city scale expands unceasingly,the vehicles also become more and more,but when people enjoying the convenient that vehicles bring,at the same time,also meet more and more problems,such as air pollution,noise pollution and traffic congestion.
The traffic light in intersections is a very important role to maintain the traffic order, guarantee the road clear. The development of urban lead to more and more vehicles. Ordinary traffic system can not meet the requirement today. So in order to Alleviate the increasing traffic pressure the intelligent traffic system [1] come.
Intelligent traffic system including the detection of road traffic, according to the intersection traffic flow characteristics and queuing delay, effectively, design a more advanced traffic signal timing scheme in order to improve the efficiency of intersection and so on.The appropriate traffic lights control strategy which can alleviate the traffic congestion is the most important topic in intelligent traffic system.
In this paper we apply the theory of double queues asymmetric gated service polling [2]  we design a traffic light system which the light time can be adjusted intellectually according to the change of the vehicles arrive rate [3].
Specific design is installing ground loop [4] in all directions 80 meters away from the intersections to count the number of vehicles,and then enter data into the computer central control system to analyze the data and calculate the waiting time through the polling model with the current arrive rate.This result of the calculation been seem as the green light time in this direction.
In this intelligent system,because the application of double queues asymmetric gated service polling theory,the load of main road which has higher arrive rate and minor road which has lower arrive rate balancing well.Considering that there are more vehicles arrive in the main road,so there need longer pass time in main road.

Polling system
Polling system model [5] consists of a server and N queues [6] .The queues arrival process and the service time are random process in queuing mode.
The double queues asymmetric gated service polling control system made up of a server,a high arrive rate queue1 and a low arrive rate queue2.The queue1 and queue2 adopt the rule which is gated service.Whatever the queue1 and queue2,the server services the current gated information packet with gated service,only,and turn to service anther queue after a conversion time.
The queue space is big enough. The number of vehicles would not more than the queue space.
For the vehicles that in the each queue, according to the principle of first-in-first-out.

Mean queue length
Define the variable

The simulation
The simulation calculation and theoretical calculation take the same parameters.
Because the main objective in this paper is find a traffic lights control strategy to balance load and alleviate traffic pressure, so the simulations is simulating peak-time road condition that the main road load 1 ρ is the double of load 2 ρ in the minor road.
In this system, there has a rang which is stable region. The stable region means in this rang of load, this system is working properly and steadily, would not occur traffic congestion and end up with the traffic system collapse. And there has a rule of the stable region is 1 ρ + ρ   ).In a real world application ,the intelligent traffic system which adopt the double queues asymmetric gated service polling theory can ensure the smooth road better.

Conclusions
Different road has different arrival rate.
Whatever in the main road which has higher load or in the minor road which is low load, the mean queue length and mean time delay increase over the system load.Compared to main road and minor road,because the main road has the higher arrive rate so there has longer waiting time and the longer green light time would be need in the real world application. And by contrasting the simulation of double queues asymmetric gated service polling theory to normal gated service polling theory ,the former is presenting advantages in the heavy load. Compute simulating result are consistent with theoretical analyses. Through above analysis, the intelligent traffic light control system which using double queues asymmetric gated service polling theory can do improve the road capacity .