Måbødalen is the dramatic valley that carries the road from Eidfjord up towards Vøringsfossen and the plateau. It is a place of old road lines, tunnels, waterfalls, and steep walls, with the feeling that the fjord landscape is being folded upward into mountain country.
Do not treat it only as transit. If you have time, stop at safe viewpoints and trailheads along the valley, where the engineering of the road and the force of the terrain are both easier to appreciate.