This paper focuses on the optimization of traffic flow on a road network, modeled by a fluid-dynamic approach. Three cost functionals that measure average velocity, average traveling time, and total flux of cars, are considered. First, such functionals are optimized for two simple networks that consist of a single junction: one with two incoming and one outgoing roads (junctions of 2 × 1 type), and the other with one incoming and two outgoing roads (junctions of 1 × 2 type). The optimization is made with respect to right of way parameters and traffic distribution coefficients, obtaining an explicit solution. Then, through simulations, the traffic behavior for complex networks is studied. The main result is that the local optimization ensures a very good result also for the complete network. This is shown by the case study of Re di Roma Square, a big traffic circle of the urban network of Rome.

Abstract. The aim of this work is to understand how urban traffic behavior, especially in cases of congestion, can be improved by an accurate choice of traffic coefficients. For this, we define three cost functionals that measure average velocity, average travelling time and total flux of cars. The global optimal control problem for a complex network is difficult to solve both from analytical and numerical points of view. Thus, we focus on a simple junction with one incoming road and two outgoing roads (junctions of 1 × 2 type), obtaining exact solutions to a simple optimization problem. Then, we use such results at each node of the network. The traffic evolution of some networks is then studied via simulations. In particular, it is shown that an appropriate choice of the traffic distributions can be useful in order to improve network conditions.

This paper concerns optimization of data traffic flows on a telecommunication network, modelled using a fluid - dynamic approach. Flows can be controlled adjusting traffic distribution and priority parameters. Two cost functionals are considered, which measure average velocity and average travelling time of packets. \ud First we address general optimal control problems, showing that existence of solutions is related to properties of packet loss probability functions. \ud A direct solution of the general optimal control problem corresponds to a centralized policy and is hard to achieve, thus we focus on a decentralized policy and provide solutions for a single node with two entering and two exiting lines and asymptotic costs. Such solutions permit to simulate the behaviour of decentralized algorithms for complex networks. Local optimization ensures very good results also for large networks. The latter is shown by case study of a test telecommunication network

No abstract

We focus on the differences among the analytical optimization of traffic flow on a road network, modeled by a fluid-dynamic approach, and a dynamic random one. In particular, two real urban networks are analyzed: Re di Roma Square, in Rome, and Via Parmenide crossing, in Salerno. With such two examples, it is possible to show that dynamic random algorithms are not the right choice for the improvement of traffic conditions.