In the last years, vehicular networking has grown up in terms of interest and transmission capability, due to the possibility of exploiting the distributed communication paradigm in a mobile scenario, where moving nodes are represented by vehicles. The different existing standards for vehicular ad-hoc networks, such as dedicate short range communication (DSRC), wireless access for vehicular environment (WAVE)/IEEE802.11p, have given to the research community the possibility of developing new medium access control (MAC) and routing schemes, in order to enhance the quality and the comfort of mobile users who are driving their vehicles. In this paper, we focus our attention on the optimization of traffic flowing in a vehicular environment with vehicle-2-roadside capability. As shown later, the proposed idea exploits the information that is gathered by road-side units to redirect traffic flows (in terms of vehicles) to less congested roads, with an overall system optimization, also in terms of carbon dioxide emissions reduction. An analytical model, as well as a set of pseudo-code instructions, have been introduced in the paper. A deep campaign of simulations has been carried out to give more effectiveness to our proposal. Index Terms-VANET, IEEE 802.11p, wireless access for vehicular environment (WAVE), dedicate Short Range Communication (DSRC), congestion, traffic flow, predictive re-routing, CO 2 emissions.
I. INTRODUCTIONI N THE last years, the interest in vehicular opportunities and potentialities has drastically grown, due to the numerous advantages inherited from mobility solutions in urban/suburban environments. In particular, Vehicular Ad-hoc NETworks (VANETs) represent a new and modern paradigm of communication, where the nodes are able to communicate in a distributed manner, based on the ad-hoc paradigm [1], [2].VANETs are going to be considered as one of the first adhoc networking reality in nowadays applications, enabling the transmission among nearby vehicles as well as between vehicles and nearby external devices. In fact, each node is equipped with a wireless device, the On-Board Unit (OBU), which is able to interact with the infrastructure equipment for comfort/security applications, trade and infotainment services.