A method is presented for reconstructing the geometry of a road from a single image of the road. The road is modeled as a space ribbon defined by a spine (centerline) and generators which are horizontal line segments cutting the spine at their midpoint at a normal angle. Properties of two neighboring generators of such a ribbon are examined, and it is found that if a generator is known, a neighbor is completely defined if one of its ends is known. The proposed method uses this property to reconstruct the visible part of the world road, by iteratively finding a series of generators. The proposed method is tested against a simple method which assumes that the ground is flat and against another method which uses vanishing points.