Effect of Ad-Hoc Vehicular Network on Traffic Flow: Simulations in the Context of Three-Phase Traffic Theory

Effects of vehicle-to-vehicle (or/and vehicle-to-infrastructure communication, called also V2X communication) on traffic flow, which are relevant for ITS, are numerically studied. To make the study adequate with real measured traffic data, a testbed for wireless vehicle communication based on a microscopic model in the framework of threephase traffic theory is developed and discussed. In this testbed, vehicle motion in traffic flow and analyses of a vehicle communication channel access based on IEEE 802.11 mechanisms, radio propagation modeling, message reception characteristics as well as all other effects associated with ad-hoc networks are integrated into a three-phase traffic flow model. Thus simulations of both vehicle ad-hoc network and traffic flow are integrated onto a single testbed and perform simultaneously. This allows us to make simulations of ad-hoc network performance as well as diverse scenarios of the effect of wireless vehicle communications on traffic flow during simulation times, which can be comparable with real characteristic times in traffic flow. In addition, the testbed allows us to simulate cooperative vehicle motion together with various traffic phenomena, like traffic breakdown at bottlenecks, moving jam emergence, and a possible effect of danger warning massages about the breakdown vehicle on traffic flow.