Thanks Zeos, I've seen the thread - you could be writing our marketing materials, as Angrypig said
There could be a special kind of a border that places the rumble strips, although currently the border just extends straight from the road surface but the rumble strips are usually steeper or shaped specially. So maybe it would be better defined as a part of the road profile with different materials assigned. Yeah, that would be the way, we only need to extend the profile specification with markings/materials and such. For common roads the gutters can be done this way too.
Road banking is possible even now, the algorithms count with it but there's no UI for it yet.
But I don't think this (and the rumble strip segments) would have to be automatically generated or randomized. I'd leave it on the track editor - unless you'd want to generate myriads of tracks around the world for some reason, and didn't want to specifically tune each one.
Joining the start and the end of a road seamlessly is of course possible, but there will be specific tools in the editor to ease making things like this and road junctions and such.