This SAE J2971 Recommended Practice Truck and Bus Aerodynamic Device Terminology document describes a standard naming convention of aerodynamic devices and technologies used to control aerodynamic forces on truck and buses weighing more than 10,000 pounds (including trailers).This recommended practice provides a detailed list and definition of truck and bus aerodynamic device terminology that may provide a common nomenclature for use in publishing data, reports and SAE recommended practices.