Evaluation of Headway Threshold-based Coordinated Platooning over a Cascade of Highway Junctions

Platooning of vehicles with coordinated adaptive cruise control (CACC) capabilities is a promising technology with a strong potential for fuel savings and congestion mitigation. Although some researchers have studied the vehicle-level fuel savings of platooning, few have considered the system-level benefits. This paper evaluates vehicle platooning as a fuel-reduction method and propose a hierarchical control system. We particularly focus on the impact of platooning coordination algorithm on system-wide benefits. The main task of platooning coordination is to regulate the times at which multiple vehicles arrive at a particular junction: these vehicles can platoon only if they meet (i.e. arrive within a common time interval) at the junction. We use a micro-simulation model to evaluate a class of threshold-based coordination strategies and derive insights about the trade-off between the fuel savings due to air drag reduction in platoons and the extra fuel consumption due to the coordination (i.e. acceleration of some vehicles to catch up with the leading ones). The model is calibrated using real traffic data of a section of Interstate 210 in the Los Angeles metropolitan area. We study the relation between key decision variables, including the platooning threshold and the coordination radius, and key performance metric, fuel consumption.