Imitation Model of Traffic Flows

Modern cities are unthinkable without the traffic control systems. Using traffic control systems you can solve a lot of traffic problems, such as traffic incidents, fuel consumption, delays, traffic jams, emission of pollutants, parking and others. Developing traffic control systems require less cost than other parts of the transport infrastructure improvements. Traffic conditions are influence a lot of factors, such as roads conditions, number of traffic directions, vehicles speed, number objects of the transport attraction, number of traffic lights, urban transport and others factors. If you want to implement traffic control system to the streets of cities you must to estimate all traffic factors. In order to implement all traffic factors you need to create traffic flows imitation model. The developed imitational model of the traffic flows permits the modeling of various traffic flows at the intersections. With the help of this imitational model the simulations at three intersections were conducted [1]. Karaliaus Mindaugo Avenue was used for experimental and for imitation of traffic flows, because the Karaliaus Mindaugo Avenue was one of the busiest streets in the Kaunas city in 2004. This fact is also indicated by the analysis of the research of the traffic flows in the city of Kaunas. In 2007 a new shopping and amusement center was opened near the Karaliaus Mindaugo Avenue and the four-story car parking lot with capacity of 2500 cars was built besides it. After the shopping and amusement center was opened the car traffic in this street increased by 26%. A new sports and amusement arena with 15000 visitor seats should also begin its operation in 2011 near the mentioned shopping and amusement center. The car parking lot with capacity of 600 cars will be built near the arena. The car traffic in the Karaliaus Mindaugo Avenue will increase even more. When the car traffic flow is increased the probability to form the traffic jams becomes very high especially in the roads and intersections around the objects of the transport attraction. Large traffic jams may also be formed after the mass public events. In order to control the traffic flows near the objects of the transport attraction the transport control imitation model has to be created [2].


Introduction
Modern cities are unthinkable without the traffic control systems. Using traffic control systems you can solve a lot of traffic problems, such as traffic incidents, fuel consumption, delays, traffic jams, emission of pollutants, parking and others. Developing traffic control systems require less cost than other parts of the transport infrastructure improvements.
Traffic conditions are influence a lot of factors, such as roads conditions, number of traffic directions, vehicles speed, number objects of the transport attraction, number of traffic lights, urban transport and others factors. If you want to implement traffic control system to the streets of cities you must to estimate all traffic factors. In order to implement all traffic factors you need to create traffic flows imitation model. The developed imitational model of the traffic flows permits the modeling of various traffic flows at the intersections. With the help of this imitational model the simulations at three intersections were conducted [1].
Karaliaus Mindaugo Avenue was used for experimental and for imitation of traffic flows, because the Karaliaus Mindaugo Avenue was one of the busiest streets in the Kaunas city in 2004. This fact is also indicated by the analysis of the research of the traffic flows in the city of Kaunas. In 2007 a new shopping and amusement center was opened near the Karaliaus Mindaugo Avenue and the four-story car parking lot with capacity of 2500 cars was built besides it. After the shopping and amusement center was opened the car traffic in this street increased by 26%. A new sports and amusement arena with 15000 visitor seats should also begin its operation in 2011 near the mentioned shopping and amusement center. The car parking lot with capacity of 600 cars will be built near the arena. The car traffic in the Karaliaus Mindaugo Avenue will increase even more. When the car traffic flow is increased the probability to form the traffic jams becomes very high especially in the roads and intersections around the objects of the transport attraction. Large traffic jams may also be formed after the mass public events. In order to control the traffic flows near the objects of the transport attraction the transport control imitation model has to be created [2].

Experimental research of the model of the traffic flows
In order to create the imitation model of traffic flows the experiment in three intersections near the shopping and amusement center with the multistory car parking lot was carried out. The data was recorder during the experiment using automatic and manual methods [3,4].

Creation of the imitational model of the traffic flows
The developed imitational model of the traffic flows permits the modeling of various traffic flows at the intersections. The main task of this imitation model is traffic jam detection. The main parameters that were measured experimentally are time of traffic ligts, distances between intersections, vehicle speed, hourly traffic flows, average lengths of the cars.
The control of traffic lights is one of the cheapest and most effective ways to reduce vehicle jams, accidents, and environmental pollution.
Optimal traffic lights control is very important at morning and evening traffic jams. Mostly traffic lights are controlled by fixed-cycle management. Traffic signals working time can be divided into several modes: stroke, major stroke, stroke phase, phase, and cycle [5].
For traffic control red and green phases are used. These phases are determined by traffic volume and traffic composition. Developing simulation model, traffic light signals were measured. Traffic light cycles are shown in Fig. 2 [2,5].     All algorithms describing the vehicle movement to the intersection and through are implemented in program "Arena". This program is made by the company of "Rockwell Software". Arena simulation software helps demonstrate, predict, and measure system performance.
The model developed with the imitational modeling software package Arena is shown in Fig. 5. probability of vehicles lane changes from one zone to another was calculated also. With the help of imitational model the simulations of the intersections 1, 2 and 3 were conducted. During the modeling in addition to the different flows KMST, KMSEN and PARK the traffic flows at the intersection 3 were measured, so that it would be possible to determine the emerging car jams in the each traffic lane.

Results of modeling with traffic flows
The rows of the vehicles at the 3 rd intersection are illustrated in Fig. 6. As we can see the traffic intensity in the second lane is almost two times higher that in the first lane. When performing the further modeling the regression flow forecasting model was used [6]. During the modeling 700, 1000, 1500 and 2000 cars were let out from the parking lot in different times of day and night. The results of the regression forecasting model and Arena modeling are given in Fig. 7. During the first stage of the modeling the flow from the parking lot was varied. It was selected that 700 automobiles leave the parking lot over one hour. The modeling results of the 3 rd intersection are presented in Fig. 8. During the second modeling stage it was selected that 1000 cars leave the parking lot over one hour. The modeling results at the 3 rd intersection are given in Fig. 9. As we can see from Fig. 8-Fig. 10, even when 700 to 1500 cars leave the parking lot, a very large car jams between the intersections 2 and 3 which would block the traffic entirely, would not be formed, since the main car traffic from the parking lot moves forward along the Karaliaus Mindaugo Avenue. The performed modeling has shown that the modes of operation of the traffic lights are selected properly enough to manage significantly large traffic flows, even when the flows of the traffic leaving the parking lot increase rapidly. Based on the results a conclusion can be drawn that the probability for the traffic jams to be formed at the 2 nd and the 3 rd intersection is highest during the time from 14 to 18 hour. Therefore a conclusion can be mane that the large public events should be avoided during this time of the day because they would attract a large number of the cars.

Conclusions
1. Intersection operation algorithms when the traffic flows move to the intersection ant through it were developed which were also implemented in the imitational model of the intersection. The simulations of the traffic flows in one of the busiest city streets were accomplished and they demonstrated that the operation of the traffic lights under the average load of the intersections is configured sufficiently properly.
2. When the traffic flow was increased up to 1500 cars per hour the traffic jams at the intersections are still manageable, and when the traffic of the cars leaving the parking lot is increased up to 2000 cars per hour, the traffic lights are not sufficient to ensure the throughput of the traffic flows.
3. The developed imitational model of the intersection can be applied to any intersection of the city.
Also the developed imitational model of the traffic flows at the intersection has a possibility to perform the modeling with the additional traffic flows which will be formed after the "Žalgiris" sports arena will be built in Kaunas.