Come around NRW, there are a couple of highways that are about the same age and still aren't finished. :)
AFAIK we still don't know where it will be built, but there has been some progress... EDIT: They agreed upon where! But they don't know when and holding another forum due to public outcry over the chosen path... sigh.
Meanwhile, Switzerland built the connection ~40 years ago [1]
But this is a special situation, a really small gap between the Swiss highway and the Austrian/German highway, so transit had to go through the villages and clogging up everything at the bottlenecks along the border (or in Höchst, Hard, Bregenz, Lustenau, Hohenems, Feldkirch etc.)
The variant that (at the time) is supposed to be built would be 8.6km.