ok^^ I'll retry it ;) thanks for the fast answer

higlhy recommended to make terrain plan before placing, with the terraforming tools, else you'll have to unbuild rebuild a few segment (happen time to time it depend)

Really cool junction, but ingame i have a problem placing it - everytime I try to connect it to the highway it a tunnel entrance is placed and the ground lowered. This happens for the connections starting at the junction, the other direction is untouched by this issue. The ground is perfectly flat.
What can I do to fix it?