Sviluppo di un modello di microsimulazione per l'analisi delle prestazioni di sistemi BRT

In recent years, both in Europe and the rest of the world, the attention focused on the study of Bus Rapid Transit systems has been growing significantly since they represent a significant way to improve mobility at relatively low cost without underestimating the challenge of sustainable mobility in urban context. Despite BRT systems having economic advantages and mobility benefits, literature lacks consolidated and generally accepted tools for planning, designing and operating BRT vehicles and facilities. Therefore, using a micro-simulation approach is a useful way to study Bus Rapid Transit design and their operational problems. The starting point of this paper is an overview of literature on the characteristics of existing BRT as well as on performance evaluation frameworks. Furthermore a dynamic micro simulation model representing a BRT system has been implemented by ARENA ROCKWELL Software. This software developed such a model through the cooperative use of dynamic Flow-Charts and static module for Data entry, each of which referred to a specific sub-process. The implemented model allows the replication of vehicle operations, including driver's decision making along the route, in passenger stations and at traffic signals. At the same time the model provides a representation of passengers waiting on the platform, travelling on board and getting off a vehicle. Moreover it has been empowered to analyze near-side, far-side and mid-stop layout for stations, taking into account the kinematic parameter variability due to different drivers. In addition, operations detailed by the model deal also with assigning a destination station to each passenger leaving from every starting station, according to a designed matrix. Moreover, the system is capable of analyzing service working at capacity, taking the vehicle's boarding limit into account when the simulation runs. This provides a higher understanding of the factors that influence and impact travel time and bus delay and provides a tool that can evaluate specific measures and alternatives to increase the efficiency and effectiveness of the system. Micro simulation modelling is useful to evaluate the effectiveness of specialized lanes, and transit signal priority, and measure the benefits and impacts of the signal priority strategy. Once the model has been defined, the calibration and validation procedure is carried out achieving a comparison between the model's output and recent literature findings. In particular, results have been compared to those obtained by an analytic model for evaluation of transit line performance. Finally, model has been tested in a real-life case study for a new BRT line in Rome.