How do interchangeable plates work?

Interchangeable plates (interchangeable number) allow two vehicles to be registered with a single licence plate, respectively a single set of plates. The central restriction: the two vehicles may never be used simultaneously — there are no day permits for simultaneous use.

The condition is that the plates of both vehicles be of the same kind (e.g. two white passenger-car plates). Vehicles with plates of a different kind (for example a tractor and a passenger car) cannot be combined on interchangeable plates.

Special case of veteran vehicles: several veteran vehicles may be registered on the same interchangeable plates — beyond the otherwise applicable two vehicles.