Architecture of (ATC)

**Figure 1:** Area traffic control architecture (Source: Pitu B. Mirchandani, K. Larry Head,1998)
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Fig. 1 is showing the arrangement of whole area traffic control system with all units of the system. These unites will be use for different-different task in the system. It could we described in three stages. At first stage estimation of is done, it is done based on the slow-varying characteristics of the network traffic load in terms of vehicle per hour than according to this estimated ATCS allow to allocate green time for each different demand for each phase. At the middle stage traffic characteristic are measured in terms of platoons of vehicle and their speeds and at last stage intersection controller select the suitable phase change based on observed and predicted arrivals of individual vehicle at each intersection.