The implementation of an advanced process for the aerodynamic development of cab-over type heavy trucks at FAW requires a rigorous validation of the tools employed in this process. The final objective of the aerodynamic optimization of a heavy truck is the reduction of the fuel consumption. The aerodynamic drag of a heavy truck contributes up to 50% to the overall resistance and thus fuel consumption. An accurate prediction of the aerodynamic drag under real world driving conditions is therefore very important. The tools used for the aerodynamic development of heavy trucks are wind tunnels and CFD. Wind tunnels have a number of limitations which make it difficult to predict on road performance of the truck. Such limitations are limited availability, blockage and pressure gradient effects, lack of road simulation and Reynolds number effects. While on the other hand CFD does not have such limitations the accuracy of CFD is often questioned and needs to be proven.