I've been really struggling to get my highways to label neatly. The idea is to have one route number label every 1 km on the route. The only issue is that there are duplicate separated carriageways with the same route number. And then the label gets added twice, for both directions of travel:
What I'm actually looking for is this (one label, placed on either side of the separated carriageway):
I've tried tweaking the variables in the labeling options, but nothing gives me this result. I also tried dissolving based on Route Number (the label field) and then labeling without placing a label on every multipart feature. This works only if there are no lines like my blue line. If the same Route Number repeats somewhere else, like in my example image, then only the one or the other gets labeled.