In the case of a dual carriageway with a left turn segment that should not permit a u-turn, is it a good practice to not have a junction node between the turn segment(s) and the segments of the opposite direction of the carriageway?
For illustration purposes, here's a Permalink
with the two turn segments highlighted. All turns are properly restricted to route correctly but would it be better/worse to eliminate the junction and have the segments cross without connecting?
The biggest problem I see would be a system generated error should someone actually make a u-turn but that isn't much different than the other problems that get reported when there is really no problem.