Modelling the impact of platooning on motorway capacity

Technology in road vehicles is continuously advancing. Vehicle-to-vehicle (V2V) communications can alert drivers of the location and movement of other vehicles, and allow those vehicles to react automatically to the behaviour of those vehicles. A natural development of this technology is the formation of ‘Road Trains’ – platoons of vehicles automatically following a lead vehicle driven by an expert driver. Such road trains can potentially improve safety, fuel consumption and use of time (in the following vehicles). This paper describes work undertaken to simulate (in VISSIM) such Road Trains on a UK motorway carriageway. It looks at the effect on the road capacity and congestion of varying proportions and compositions of road trains (HGV only vs mixed HGV and cars). The study concentrated on established road trains on the main carriageway alone, finding a small increase in carriageway capacity approximately proportional to the percentage of all vehicles travelling in road trains.