By definition a super elevation is the amount by which the outer edge of a curve on a road or railroad is banked above the inner edge. To counter-act the effect of centrifugal force and reduce the tendency of vehicle to overturn and to skid laterally outwards, pavement outer edge is raised with respect to inner edge. Thus, providing a transverse slope is known as Super elevation. It is represented by ? e ?.
See these sketches and calculations that will help you better understand this.