Fuel Consumption of Adaptive Cruise Control Platoons: Bench Experiments and Data-Driven Estimation for Real Traffic

Vehicles equipped with adaptive cruise control (ACC) systems are expected to improve traffic safety and decrease fuel consumption. Recent experimental studies have shown that ACC leads to string instability in the case of platooning and can, therefore, result in higher energy needs compared with a platoon of human-driven vehicles (HDV). However, the impact of ACC on fuel consumption in the case of platooning and the global impact of ACC fuel overconsumption in traffic are not known yet. This study examines the impact of ACC systems on traffic fuel consumption using experimental data and traffic records. In this study, we inject the speed profiles of ACC and HDV platoons that follow a similar leader trajectory into an engine bench. Then, we identify the event that leads to an overconsumption of fuel in the case of platooning. The results of the engine bench show that only ACC platoons of six or more vehicles with a short time-gap setting consume more fuel than HDV platoons. Using HighD and ExiD records, we detect if the events leading to fuel overconsumption often happen in traffic. The results on HighD and ExiD show that such an event happens once out of 1,250 episodes if we divide the time into episodes of 15 s. This shows that, even if fuel overconsumption exists in specific cases, those cases are actually too rare in traffic to affect global fuel consumption.