Structural Complexity of Traffic Lights Control Based on Petri Net

The signals order of the standard traffic light is green, yellow/ amber, red, and return to the green signal becomes a cycle. The Norwegian traffic light is more complicated than the standard traffic light. The Norwegian traffic light has one more stage, i.e., red-yellow that lights simultaneously. This state is at the end of the red signal. The modification of the Norwegian traffic light changes the fourth stage into a light yellow color only. This study investigates the structural complexity of the control system based its Petri net model. The structural complexity is the indicator of interrelationship in a system. The improvements in the functions of the devices increase in system complexity. The structural complexity of the Norwegian traffic light control system is the highest, and the second is its modification. The standard traffic light is the lowest. Both the Norwegian and the modification of the Norwegian traffic lights have a steady downward trend in complexity approaching ideal while the number of phases and features increases. However, the traffic lights of a standard type, its complexity fluctuates.