CEA, LIST Huawei Technologies Mines ParisTech Retired Futurewei This document describes the use-cases of Cooperative Adaptive Cruise Control, and Platooning, as defined by several Standards Development Organizations such as ETSI, IEEE P1609, SAE, 3GPP, ISO and FirstNet. C-ACC and Platooning involve concepts of direct vehicle-to-vehicle, and device-to-device communications, which are developed by 3GPP following on work done within the METIS EU project. They are illustrated very clearly in emergency settings such as FirstNet. IP packets - instead of link-layer frames - are pertinent for C-ACC and Platooning use-cases because applications for road safety such as WAZE, iRezQ and Coyote (currently involving infrastructure) make use of IP messages, and have proved successful in deployments. Applications such as Sentinel operate directly between vehicles, but currently use messages not carried over IP.