This paper addresses collision avoidability analysis of a platoon of vehicles under Vehicle-to-
Vehicle-to-Infrastructure(V2V2I) communication. We first present a system consisting of vehicular
strings and infrastructure in connection. Each vehicle drives automatically connecting others under
Vehicle-to-Vehicle(V2V) communication, infrastructure inputs desired inter-vehicular distance to
platoon to control safety under Vehicle-to-Infrastructure(V2I) communication. Then we analyze
collision avoidability of the vehicle platoon, where we show relationship between communication
structure and controllability of safety from infrastructure.