Narrow Results

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.

Among real-system applications of AI, the field of traffic simulation makes use of a wide range of techniques and algorithms. Especially, microscopic models of road traffic have been expanding for several years. Indeed, Multi-Agent Systems provide the capability of modeling the very diversity of individual behaviors. Several professional tools provide comprehensive sets of ready-made, accurate behaviors for several kinds of vehicles. The price in such tools is the difficulty to modify the nature of programmed behaviors, and the specialization in a single purpose, e.g. either studying resulting ows, or providing an immersive virtual reality environment. Thus, we advocate for a more exible approach for the design of multi-purpose tools for decision support. Especially, the use of geographical open databases offers the opportunity to design agent-based traffic simulators which can be continuously informed of changes in traffic conditions. Our proposal also makes decision support systems able to integrate environmental and behavioral modifications in a linear fashion, and to compare various scenarios built from different hypotheses in terms of actors, behaviors, environment and ows. We also describe here the prototype tool that has been implemented according to our design principles.

Acoustic barriers are a well-known environmental noise mitigation solution, which is widely used nowadays. In this work, it is expected to contribute to the body of knowledge regarding the physical and technical behavior of those barriers by developing and implementing a set of models that allow an accurate analysis of noise barriers with new configuration types. A 2.5D boundary-only numerical model is developed and implemented, and computational analyses are performed in order to compare different surface profiles of the acoustic barriers. The particular case in which two acoustic barriers are used, one at each side of the road, is addressed.

In this paper, the macroscopic model for traffic flow proposed by Aw and Rascle in 2000 is considered. The model is a 2 × 2 system of hyperbolic conservation laws, or, when the model includes a relaxation term, a 2 × 2 system of hyperbolic balance laws. The main difficulty is the presence of vacuum, which makes control of the total variation of the conservative variables impossible. We allow vacuum to appear and prove the existence of a weak entropy solution to the Cauchy problem.