On-Road Investigation of Energy Saving Opportunity for Autonomous Light-Duty Vehicles through Automated Vehicle-Following in Safe Distance Scenarios

Reducing aerodynamic drag through Vehicle-Following is one of the energy reduction methods for connected and automated vehicles with advanced perception systems. This paper presents the results of an investigation aimed at assessing energy reduction in light-duty vehicles through on-road tests of reducing the aerodynamic drag by Vehicle-Following. This study provides insights into the effects of lateral positioning in addition to intervehicle distance and vehicle speed, and the profile of the lead vehicle. A series of tests were conducted to analyze the impact of these factors, conducted under realistic driving conditions. The research encompasses various light-duty vehicle models and configurations, with advanced instrumentation and data collection techniques employed to quantify energy-saving potential. The study featured two sets of L4 capable light duty vehicles, including the Stellantis Pacifica PHEV minivan and Stellantis RAM Truck, examined in various lead and following vehicle configurations at different speeds with cruise control enabled. Energy savings per km in the range of 9-17% were observed in Pacifica and savings up to 25% were obtained in RAM within 1-2 seconds following gap for speeds of 55-75 mph. It was also observed that the lateral positioning has a significant impact on energy saving overall. The results are also compared to the previous studies on drag reduction in two-vehicle platoons. This investigation contributes valuable knowledge to the vehicle-following to reduce the aerodynamic drag and thus to reduce the overall energy consumption in the highway driving scenarios. This can also be used in advanced vehicle positioning controls in autonomous vehicles where advanced sensing of the relative positions can be estimated accurately. The results give insights into optimizing energy efficiency, with a focus on the role of Vehicle-Following, aerodynamic drag reduction, and lateral positioning strategies for sustainable and environmentally conscious road transportation.