Abstract
In the current highway design, a center curve of a highway is designed in three steps. In the first step the projection of the center curve onto the horizontal plane is designed with planar curves, i.e. x=x(t), y=y(t) consisting of straight lines, circular arcs, and clothoid curves. Secondly, the elevation z=z(t) is designed separately. Finally, the super elevation, which is the tilting of the road to account for the centripetal forces as the vehicle goes around a curve, is considered. Therefore, the resulting 3D curve may pass through the desired positions and tangents, however, in general, it does not have the correct normal and binormal vectors. In this research, we introduce a new method to generate the center curve with correct positions, tangents and curvature vectors at the input positions. Then, the section curves are generated along the normal vector at each input position, and blended together to form a lofted surface.
