Capacity Predictions and Capacity Passenger Car Equivalents of Platooning Vehicles on Basic Segments

Vehicle platooning is an innovative strategy that uses automated driving technology and communication to enable a more efficient use of transportation networks. By controlling tighter gaps between vehicles, vehicle platooning will increase freeway capacity. However, it is important to quantify the extent of the increase of capacity so that highway engineers can plan for this technology. This Federal Highway Administration research develops an analytical model to predict the capacity of basic freeway segments based on the market penetration and the maximum number of vehicles allowed in a platoon. It uses these predictions to calculate passenger car equivalents, which may be required for planning purposes. Simulations show that capacity can be predicted analytically to within 2% of simulated values. In addition, for the parameters used in the analysis, the capacity of freeways that restrict platoons to no more than 5 vehicles is comparable to the capacity of freeways that allow larger platoons (e.g., 6.1% maximum difference in capacity between maximum 5 and 12 vehicle platoons); consideration of limiting platoon size is important to ensure maneuverability.