This paper summarizes and compares the two main test methods for aerodynamic evaluations of heavy trucks in the United States and the European Union: coastdown testing and constant-speed testing, respectively.

This study compares official fuel consumption values measured in laboratories with the real-world performance of 20 popular vehicle models. All models claim significant improvements in fuel efficiency since 2009, with reductions in official fuel consumption values ranging from 8 to 30 percent.