A Route Guidance System Against Traffic Congestion Following a Constrained System Optimal Model

In-vehicle route guidance systems are increasingly being used both to provide assistance to drivers and to manage traffic in such a way that allows an increase in road network capacity and therefore a decrease in traffic congestion. A typical route guidance system makes use of current traffic conditions in order to compute the shortest route to the driver’s destination. This paper considers the application of the basic principles of the Constrained System Optimal model, used to solve the traffic assignment problem, in the case of routing a single vehicle. This model is a combination of the two previous approaches, where a global objective is set in order to ensure the effectiveness of the system and at the same time constraints guarantee the fairness of the recommendations for the drivers. The authors outline the idea of equilibrium in transportation systems and the basic principles of the traffic assignment problem, before presenting details of the proposed model for route guidance systems. The authors conclude that, compared to the User Optimal model that provides no traffic improvement guarantees and the System Optimal model that is unrealistic, the Constrained System Optimal solution adopts the goal of reducing congestion and at the same time remaining fair for drivers with respect to the individually shortest route to their destination.