This paper presents the development of a suitable accurate CFD vehicle drag prediction methodology employing the commercially available numerical prediction tools within FORD OTOSAN Company, Turkey. FLUENT flow analysis and ANSA grid generation software are extensively used by FORD OTOSAN for their vehicle drag predictions towards a greener vehicle development and competitiveness in the related market. The present work aims to extend the previously developed RANS methodology to the efficient usage of detached eddy simulation (DES) towards more detailed prediction and better understanding of flow field for automatic optimization of designed vehicle geometries. The optimum FLUENT and ANSA parameters are determined for the general unsteady analysis of light commercial road vehicles designed by FORD OTOSAN. These design parameters include the time step size, solver type, convergence criteria, boundary layer mesh details, grid growth coefficient, and total number of grid points. The DES analyses are presented both for a test geometry and the actual FORD OTOSAN geometry in comparison with other RANS and DES predictions as well as available measurements. The advantages and disadvantages of using DES for the drag predictions are also elaborated.