Nowadays, traffic is the most tangible and urban traortation problem and it cause the form of shortcomings such as delays in travel time, noise pollution, and accidents and so on. In this order, the timing of traffic lights could plays an important rule. The main object of a proper timing of traffic lights in an intersection is reducing the average delay of vehicles, as well as reducing the number of accidents. Graphs theory is applied as a powerful tool in studying and solving problems in real world life
