How is IfcReferent used to indicate transitions for cross-sections?

I’m reading the description of IfcReferent in and it says “Referents may be used for several scenarios: … * indicating transitions for cross-sections (e.g. beginning of curvature where road is relatively flat, maximum curvature having super-elevated cross-slope to accomodate design speed)”

How are roadway surface transitions (superelevations) defined?