Traffic control system is an interconnection of signaling devices positioned at road intersections, pedestrian crossings and other locations to control competing flows of traffic. This paper presents basic notions and application procedures of Priority Based Automatic Traffic Control Mechanism, and outlines current and potential applications of these methodologies for efficient traffic and transportation control systems. This mechanism is necessary and it may be applied to modern cities wherever particular paths have more traffic jam compared to other paths signals. This mechanism is well suited for controlling the traffic of old cities which are not preplanned before construction. But if we are going to construct a preplanned city we may choose appropriate traffic control mechanism to control the traffic. This paper discusses general concepts of traffic control mechanism and proposes priority based scheduling algorithm for automatic traffic control mechanism.