Procedural roads on sloppy landscapes

[ritoo]

After watching this nice tutorial about procedural park in flat surface:
https://www.youtube.com/live/BK-qAvVMqmU?si=Agt5KYi6aIfjOfEy&t=5230
I'd like to ask how flat* paths could be procedurally put on slopped landscapes?
I guess it's not 100% FP question but still..
*- I mean flat in local section (AB in the attached picture)