Describe it how it is ' Primary Position' then show them on a diagram, & best of all show them on the road.
No need for diagrams.
They either are riding in a position where they prevent drivers from overtaking in the lane they are using (primary) or where drivers have room to overtake so the allow them to overtake -Secondary . Simple
@user73707 started
The Association of Bikeability Schemes.
Level3
@user73707
Describe it how it is ' Primary Position' then show them on a diagram, & best of all show them on the road.