The SARTRE Project (Safe Road Trains for the Environment), is a European Commission funded project investigating implementation of platooning on unmodified European motorways. The project begun in September 2009, and vehicle platooning, as envisaged by the SARTRE project, is a convoy of vehicles in which a professional driver in a lead vehicle heads a line of closely following vehicles. Each following vehicle autonomously measures the distance, speed and direction and adjusts to the vehicle in front. Once in the platoon, drivers can do other things while the platoon proceeds towards its long-haul destination. All vehicles are detached and can leave the procession at any time.