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 (CTHP) and availing the on-board information of predecessor's vehicle position and velocity, the minimum employable time headway (hmin) must be lower bounded by 2τ0 for string stability, where τ0 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 4τ0/(1+r); (2) furthermore, if the acceleration of `r' immediately preceding vehicles is used, then hmin can be reduced to 2τ0/(1+r); and (3) if the position, velocity and acceleration of the immediate and the r-th predecessors are used, then hmin ≥ 2τ0/(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.