A Simplified road vehicle (Ahmed body) with a square-backed shape was placed in a freestream flow velocity 40m/s corresponding to a high Reynolds number Re= 7.6 × 10 5 and experienced in a wind tunnel, in the same time in parallel a simulation was done in the same real conditions with different turbulence models. The main goal from this study was to examine the effectiveness of the DDES and k − ω SST turbulence models in presenting such complex flows. To certify the accuracy of the turbulent models many physical parameters were compared to experimental data, from boundary layer parameters to the wake characteristics, shear layer and mass entertainment. A great agreement were found between experiment and DDES model. In other hand a simulation was done to certify the effects of ground clearance and 5% of drag reduction was obtained by changing it from 50mm to 45mm.