This simple agent-based model utilizing MASON was created by Omar Guerrero as part of his comprehensive exams. Omar, built the model to explore the question: what is more effective, a four way stop or a traffic light at a road intersection?
The rules of the model are simple, in the sense that at a four way stop, the vehicle that is first to arrive, it is first to move, unless two vehicles arrive at the intersection at the same time and then the vehicle has to give way to the car on the right. While at traffic lights vehicles must stop at red lights. The movie below shows part of the graphical user interface for a particular model run of both a four way stop and traffic light.
Even though this is a simple model, one can explore a number of issues such as how these different intersection configurations impact on the flow of traffic under different volumes of traffic. For example, at low traffic volumes in general, the stop sign is more effective (i.e. allows more cars to cross) than the traffic light. However, at greater traffic volumes the traffic lights out performs the four way stop (in the sense there are more cars in queues) but also with high traffic volumes, one can see oscillations in traffic waiting at the lights while the four way stops create long queues of traffic as shown in the figure below.