Platooning vehicles present novel pathways to saving fuel during transportation. With the rise of autonomous solutions, platooning becomes an increasingly apparent sector requiring the application of this new technology. Platooning vehicles travel together intending to reduce aerodynamic resistance during operation. Drafting allows following vehicles to increase fuel economy and save money on refueling, whether that be at the pump or at a charging station. However, autonomous solutions are still in infancy, and controller evaluation is an exciting challenge proposed to researchers. This work brings forth a new application of an emissions quantification metric called vehicle-specific power (VSP). Rather than utilize its emissions investigative benefits, the present work applies VSP to heterogeneous Class 8 Heavy-Duty truck platoons as a means of evaluating the efficacy of Cooperative Adaptive Cruise Control (CACC). VSP creates a bridge between types of passenger vehicles to compare emission rates via estimating powertrain effort to maintain current conditions (speed, acceleration, road grade, etc.). In this study, different controller strategies and platoon configurations are examined to determine the applicability of VSP to controller evaluation. Experiments were completed at the National Center for Asphalt Technology (NCAT) circuitous track, the American Center for Mobility’s (ACM) freeway loop, and a straight section of NCAT’s track dubbed “ideal” for platooning efficiency. One truck is analyzed and compared to a lead truck, where VSP traces are calculated at each time step of experimentation. The influence of road grade, platoon size, and platooning position is considered in this study. Because the calculation of VSP considers an isolated driving environment, it effectively assesses the controller’s ability to reduce energy consumption for platooning vehicles.