  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 three-phase 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.
