Variable Speed Limit (VSL) system applications in motorways

Transport system is the relationship between locations, infrastructures and flows in road, see, air and rails. Nowadays, many social, economic and environmental problems are caused by the increase of transport system's users in different models of transport. Motorways were developed to provide high speed non-stop routes for vehicular traffic, reserved for the high-speed circulation of motorized vehicles (cars, motorcycles, heavy goods vehicles). Growing traffic on motorways has created a need for a system which can manage traffic efficiently without expanding the infrastructure. Traffic jams and volatile weather conditions in motorways cause waste of time and fuel as well as increase accident risk and pollution. Intelligent Transportation Systems (ITS) are used to minimize these problems. One of the ITS applications is the Variable Speed Limit (VSL) systems in which speed of traffic stream is decreased in small values in order to reduce the propagation of shockwaves during congestions, improve road safety by reducing collision risks and increase motorways efficiency. In this paper we aim to present VSL system benefits and applications. A brief review about approaches, methods and simulators used for traffic modeling is made, we found that the microscopic approaches are more used especially in this era of hyper-connectivity between objects.