Yes and no.
"Kraftfahrstraßen" or "Schnellstraßen" as well as "Autobahnen" are generally off-limits to cyclists and pedestrians. So there's no need for an extra sign. They all have the distinctive blue signs.
"Bundesstraßen" are usually allowed for cyclists, but in some parts they aren't which is then shown by the sign.
This is because "Bundesstraßen" can vary greatly in size. The larger a street seems, the higher the possibility to be cars only, I guess.
Yes and no.
"Kraftfahrstraßen" or "Schnellstraßen" as well as "Autobahnen" are generally off-limits to cyclists and pedestrians. So there's no need for an extra sign. They all have the distinctive blue signs.
"Bundesstraßen" are usually allowed for cyclists, but in some parts they aren't which is then shown by the sign.
This is because "Bundesstraßen" can vary greatly in size. The larger a street seems, the higher the possibility to be cars only, I guess.