Stability and string stability of platoons equipped with Cooperative Adaptive Cruise Control (CACC) is widely discussed in literature. However, safe behavior of a vehicle in a platoon, i.e., making sure that a vehicle is not involved in a collision with its preceding vehicle, is not considered to a large extent. This paper exploits techniques from invariant set theory to perform a safety analysis of vehicle behavior in a platoon. Here, regions in the state space are determined that guarantee safe behavior of a vehicle for all future time. These so-called safe sets are determined for CACC under various circumstances, in particular with and without wireless inter-vehicle communication. The proposed safety analysis framework supports real-time safety monitoring in vehicles.
