Benefits of V2V Communication for Autonomous and Connected Vehicles

In this paper, we investigate the benefits of vehicle-to-vehicle (V2V) communication for autonomous vehicles and provide results on how V2V information helps reduce employable time headway in the presence of parasitic lags. For a string of vehicles adopting a constant time headway policy and availing the on-board information of predecessor's vehicle position and velocity, the minimum employable time headway (h(min)) must be lower bounded by 2 tau(0) for string stability, where tau(0) is the maximum parasitic actuation lag. In this paper, we quantify the benefits of using V2V communication in terms of a reduction in the employable time headway: 1) If the position and velocity information of r immediately preceding vehicles is used, then hmin can be reduced to 4 tau(0)/(1 + r); 2) furthermore, if the acceleration of 'r' immediately preceding vehicles is used, then hmin can be reduced to 2 tau(0)/(1 + r); and 3) if the position, velocity, and acceleration of the immediate and the r-th predecessors are used, then h(min) >= 2 tau(0)/(1 + r). Note that cases (2) and (3) provide the same lower bound on the minimum employable time headway; however, case (3) requires much less communicated information.