Underground belt can be placed directly on normal belt. Additionally, placing an underground belt will remove any normal belts facing the same direction between the end points (as in Quick UG).
Was just thinking this as well. Although I haven't had a chance to try this mod yet, it theoretically does exactly what I've been wanting. And, splitters would be another major improvement, particularly for main bus designs.
Oh, believe me, I tried. I think there's a limitation in the fact that the splitter and the belt are different sizes (1x1 vs 1x2). Can't be done, sadly :(
