An automotive lightguide (10) includes a main guide portion (20) with a light entrance surface (12) and a reflective rear edge surface (14); and an exit lens (25) joined to the main guide portion (20), the exit lens (25) having an exit surface (18) with an arcuate exit profile (26). In use, light rays from a light source (5) enter the main guide (20) portion through an entrance surface (12), travel through the main guide portion (20) and reflect off the rear edge surface (14) to the exit lens which images the reflected light rays as a light beam pattern having a predetermined sharp horizontal cutoff and a predetermined horizontal spread, the arcuate profile (26) of the rear edge surface (14) determining the horizontal cutoff and vertical spread of the light beam pattern with respect to the horizontal optical axis H-H, and the exit profile (26) of the exit lens (25) determining the horizontal spread of the light beam pattern.