Test Procedures for the Evaluation of Aerodynamic Drag on Full-Scale Vehicles in Windy Environments

Procedures for conducting full-scale coast down tests for the purpose of determining the aerodynamic drag forces on tractor-trailer trucks are presented. Tests were conducted on the baseline vehicle and on the baseline vehicle modified with drag reduction devices. Techniques for the evaluation of mechanical drag forces prior to the coast-down tests are given and a description of the instrumentation is included.