Effects of V2V Communication on Time Headway for Autonomous Vehicles

In this paper, we investigate the benefits of Vehicle-to-Vehicle (V2V) communication for autonomous vehicles employing a Constant Time Headway Policy (CTHP). It is known that ACC equipped vehicles employing a CTHP must maintain a time headway that is lower bounded by 2 tau(0) for string stability, where tau(0) is the maximum value of parasitic actuation lag. We show the following: (1) if acceleration of preceding vehicle (obtained via V2V communication) were also to be used, then the minimum employable time headway can be reduced to tau(0) (2) if the position and velocity information of r immediately preceding vehicles ahead were to be used, then the minimum employable time headway can be reduced to 4 tau(0) / (1 + r); and (3) furthermore, if the acceleration of 'r ' immediately preceding vehicle is used, then the minimum employable headway can be reduced to 2 tau(0) / (1 + r).