When is an amber rotating or flashing beacon (gelbe Rundumleuchte / Rundumkennleuchte) permitted or required on an agricultural vehicle under KFG § 20?

1. When the vehicle presents a particular hazard to other traffic through its width, length, slow speed or the work it is doing, such as wide implements, slow road transport or road maintenance
2. On every journey on a public road, regardless of the vehicle's width or speed
3. Only when the tractor is being towed away after a breakdown
4. Only on private farm tracks, never on public roads