Evaluation of traffic control methods at traffic circles

Based on the traditional traffic flow theory and traffic control methods that is being used widely, we used Fluid Theory to describe and model the traffic flow in macroscopy, and developed a new variable, traffic-entropy, to represent the chaos level of a traffic circle from a microscopic view. We studied the 3-way circle with single-lane first and developed a detailed simulation methodology to test the performance of different control strategies. Then, we developed the model to the universal situation of N-way circles. We came up with a special theory to describe chaos and used traffic-entropy as a measure standard. Here, we focused on the pre-weaving section of each traffic circle. In addition, we came to the consideration of traffic-density and discuss the advantage of traffic lights in traffic-saturation control and entropy control. Of course, such goodness is gained with some lost, with limiting its usability. More detail was discussed in the paper and efficient advice will be given for each situation.