hello, the gap you see is the "end of the road" which is not filled as the road itself is like a thin plane. I have highlighted the profile in red in my screenshot. If you want a flat road, with a flat profile, set "Border Height" and "Inside Height" to 0.
You might still see a small gap, though.
What we might add, is an offset attribute, to allow you to intersect a bit the side borders of the road when it has the default profile. Would that be what you need?