شبیه سازی ساختمان مدل تقاطع ترافیک

Designers of traffic systems might take advantage of the simulation-before-construction approach that allows them to study the behavior of a new or existing system by use of simulation models. Nevertheless, the use of simulation models is often hindered by the fact that the model building activity is a critical, time consuming and error prone activity if performed by use of experience and intuition only. Moreover, traffic designers do not usually have the necessary skills to effectively carry out system simulation. This paper overcomes such problems by introducing a model building method, thus enabling traffic designers to seamlessly introduce simulation-before-construction into their best practices. The method is applied to the building of simulation models of traffic intersections, with an example application to a real-world intersection.

Designers of traffic systems might take advantage of the simulation-before-construction approach that allows them to study the behavior of a new or existing system by use of simulation models. The simulation-before-construction approach can effectively be used either to gain insights into the system operation, before implementation, or to develop operating policies to improve the performance of an existing system. Discovering that the just deployed traffic system is not able to accommodate the expected traffic load is indeed an example circumstance that may result in costly reworks and considerable inconveniences for users. Nevertheless, the application of simulation to the design of traffic systems is not yet widely accepted as one would rightly expect. The reason is two-fold: (1) The traffic designer is not a simulation expert and does not hold the skills necessary to build a simulation model. (2) Model building is traditionally carried out informally and thus can be an error-prone activity. A traffic system consists of various components, among which the traffic intersection is one of the most important. This paper introduces a step-wise method to formally specify and build simulation models of traffic intersections. The method is applied to a traffic intersection that consists of two intersecting roads, each with one or more lanes (either one or both ways), and a set of synchronized traffic lights that manage the flow of vehicles. The proposed method builds a simulation model from the informal description of the traffic intersection. To this purpose, the paper first illustrates how to formally specify the traffic intersection, which is usually described by informal textual descriptions or diagrammatic sketches. The formal specification is then used to build the simulation model. To give an evaluation example the model is evaluated to obtain indicators of the intersection performance and analyze the behavior of the vehicular flows at the intersection. The obtained model can be effectively used both to predict the configuration effects on the behavior of a new traffic intersection and to assist the designer in analyzing a current intersection to improve its efficiency. The designer who is in charge of taking decisions about different intersection alternatives can effortlessly build the simulation model and then evaluate it to choose the alternative that better serves the expected vehicles workload, by choosing, e.g., the appropriate number of input and output lanes, the timing of the traffic lights and the allowed directions for incoming traffic.

This paper has introduced a method to formally specify traffic intersections and to automatically build simulation models from the formal specification. By use of the model building method traffic designers are enabled to easily carry out the simulation analysis of the intersection, even though they are not familiar with simulation. The proposed method is used to build an example simulation model of a given traffic intersection, in order to assist the designer in analyzing the intersection and improving its efficiency. The proposed approach can be considered as a first step towards the use of model building methods for the simulation of complete traffic systems, consisting of multiple coordinated intersections. This paper could thus stimulate further research to extend model building to such a more complex scenario.