This paper introduces a new systematic workflow for the rapid evaluation of energy-efficient automated driving controls in real vehicles in controlled laboratory conditions. This vehicle-in-the-loop (VIL) workflow, largely standardized and automated, is reusable and customizable, saves time and minimizes costly dynamometer time. In the first case study run with the VIL workflow, an automated car driven by an energy-efficient driving control previously developed at Argonne used up to 22 % less energy than a conventional control. In a VIL experiment, the real vehicle, positioned on a chassis dynamometer, has a digital twin that drives in a virtual world that replicates real-life situations, such as approaching a traffic signal or following other vehicles. The real and virtual systems interact in a close-loop fashion: the automated driving control directs accelerator and brake pedals based on measurements from the real vehicle and from the perception of the digital twin’s surrounding virtual environment; the resulting speed of the vehicle is fed back to the virtual world to compute the position of the digital twin. The VIL workflow provides a systematic linkage between the virtual environment, the hardware and software that interact with the vehicle and the dynamometer, as well as processes that facilitate scenario setup, code generation, experimentation, and data collection. Argonne’s RoadRunner, a simulation tool dedicated to the energy-focused study of connected and automated vehicles, serves as the virtual environment and is the backbone of the workflow. The real vehicle is tied to the chassis dynamometer, and a robotic driver actuates the accelerator and brake pedals based on the demands from the automated driving controls. During experimentation, the virtual environment, the data acquisition, the automated driving controls, as well as the low-level controls are run on a real-time system (dSPACE’s MicroAutoBox).