Embodiments include a mud flap having a barrier section configured to intercept and deflect matter discharged from the tire when rotating during vehicle operation. The barrier section including a plurality of horizontal louvers, each horizontal louver forming an elongate member having a length extending primarily in a direction of the mud flap width, where the plurality of horizontal louvers are spaced apart in the direction of the mud flap height in the form of an array, where the plurality of horizontal louvers are configured to intercept and deflect matter of a minimum size traveling along any linear trajectory path from the outer circumference of the tire/wheel assembly towards the front side of the mud flap while substantially maximizing the spacing between adjacent louvers to minimize aerodynamic drag. Other embodiments provide a method of using the mud flap.