They started building this route in 1991 right after German reunification (it connects the old East with the West). Parts of the route were built in the followi

They started building this route in 1991 right after German reunification (it connects the old East with the West). Parts of the route were built in the following years. A part of the route goes through difficult terrain. It's a completely new route that now contains 27 new tunnels and 37 new bridges, some kilometers long. All this through an environmentally sensitive area. So it was quite expensive and difficult to agree on. Work was even stopped on this part at some point around 2000, mainly because of the costs IIRC.