Reflectional Symmetry Breaking (RSB) modes of the flow past parallelepiped bodies are shown to exist at large Reynolds numbers. They are reminiscent of a steady RSB bifurcation at low Reynolds number and appear as a new feature of 3D bluff body aerodynamics associated to wake multistability. The seminar will present original results about the condition of appearance as a function of ground proximity and base body aspect ratio. Experimental sensitivity analysis will be applied to characterize the RSB modes and to estimate their contribution to the total drag. Eventually, direct applications to car aerodynamics will be demonstrated through real car experiments in the industrial wind tunnel S2A.