Design and Implementation of An Intelligent Traffic Light System

The main object of this paper i s to design and implement an i ntelligent traffic light system. The sys tem is able to sense the prese nce or a bsence of v ehicles within cer tain range, by setti ng the a ppropriate duratio n for the traff ic signals to react accordingly. The simulation of the intelligent traffic signal system is done using E lectronic Work Bench Package (EWB). Th e new timing scheme promises an improvement in the c urrent traffic light s ystem. This system i s feasible, affordable and ready to be implemented especially during peak hours.


Introduction
The operation of standard traffic lights which are currently deployed in many junctions, are based on predetermined timing schemes, which are fixed during the installation and remain until further resetting.The timing is no more than a default setup to control what may be considered as normal traffic.Although every road junction by necessity requires different traffic light timing setup, many existing systems operate with an over-simplified sequence.This has instigated various ideas and scenarios to solve the traffic problem.To design an intelligent and efficient traffic control system, a number of parameters that represent the status of the road conditions must be identified and taken into consideration [1].Road traffic is very much affected by time based traffic light controllers.When waiting for a traffic light, the driver looses time and the vehicle uses fuel.Hence, reducing waiting times before traffic light can save billions of dollars annually [2].
In practice, most traffic lights are controlled by fixed-cycle controllers.A cycle of configurations is defined in which all traffic gets a green light at some point.The split time determines for how long the lights should stay in each state.Busy roads can get preference by adjusting the split time.The cycle time is the duration of a complete cycle.In crowded traffic, longer cycles lead to better performance.The offset of a cycle defines the starting time of a cycle relative to other traffic lights.Offset can be adjusted to let several lights cooperate, and for example create green waves [3].One common approach to try to handle traffic congestion is to build infrastructure, such as roads and bridges by pass lane, fly over etc.But in the past year, it is becoming increasingly more difficult to build more infrastructures to at least diminish traffic jams.Not only the height cost, but also the lack of space and the environmental damage of building new road have to be considered.A different approach is needed, based on the applying intelligent in order to manage traffic flow in a more effective and efficient manner [4].

Intelligent Traffic Light System
An intelligent traffic light system senses the presence or absence of vehicles and reacts accordingly.
The idea behind intelligent traffic systems is that drivers will not spend unnecessary time waiting for the traffic lights to change.An intelligent traffic system detects traffic in many different ways.The traffic signal system consists of three important parts.The first part is the controller, which represents the brain of the traffic system.It consists of a computer that controls the selection and timing of traffic movements in accordance to the varying demands of traffic signal as registered to the controller unit by sensors.The second part is the signal visualization or in simple words is signal face.Signal faces are part of a signal head provided for controlling traffic in a single direction and consist of one or more signal sections.These usually comprise of solid red, yellow, and green lights.The third part is the detector or sensor.[5].
Sensor is a crucial element in an intelligent traffic control.The most common sensor is inductive loop.It is very common in vehicle actuated system to detect vehicle presence.It is also very common in an urban traffic control system to count the number or to measure headway of approaching vehicles.However, the main drawback of the inductive loop is its failure to measure queue length accurately.Another type of sensor is video detection system.This system is very flexible and able to carry out traffic count and measure queue length accurately.The price of commercial video detection system is very high as compared to inductive loop system.However a local institution has developed a low cost video detection system with the same capability as the commercial system. [4].

The Proposed System
The road intersection and the traffic light system are depicted schematically in Figure ( This will give a positive effect to the green house effect towards the environment.The intelligent traffic system will also save the motorists' time and reduces their frustration while waiting for the lights to change since it helps reducing congestion in the traffic intersections.

Figure
Figure (1): Schematic view of road intersection and traffic light system Figure (3): CAR COUNTER Circuit.

& Tech. Journal, Vol.28, No. 15, 2010 Design and Implementation of an Intelligent Traffic Light System .
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com Eng. & Tech. Journal, Vol.28, No. 15, 2010 Design and Implementation of an Intelligent Traffic Light System . 5083 Table (1): The relationship between the CNTR_4SBIN and the lights of the traffic light.
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