About Direction of travel and overtaking bans: D-signs and F-signs: which statement is WRONG?
F3 specifically bans TRUCKS from overtaking motor vehicles, not cars or other drivers.
Sign F1 bans everyone from overtaking: motor vehicles may not pass cyclists or moped riders either.
The duty is following ONE OF the directions shown on the sign — both displayed arrows are equally valid, there is no primary and fallback direction.
The duty is the direction shown on the sign — the arrow determines the direction, not the code itself; the same code D4 can point a different way with a different arrow.
Explanation
trap: object of the ban read too broadly. **F1 bans motor vehicles from overtaking EACH OTHER**; mopeds are not motor vehicles, so passing a moped rider does not fall under it