The number plate BUS-A instead of KN-A
When a person from Buesingen drives through another German city, parks his car there and returns to the parked vehicle after a while, he quite often notices other people having a close look at the number plates and then start discussing about it: “BUS-A… I’ve never seen this before… how can there be a number plate with those letters?”

But it exists. There are about 700 cars, who carry those (non Buesingen people would call them “exotic”) number plates. And this is why: Buesingen belongs to the administrative district of Konstanz, so in fact, there should be number plates with the initials KN-… on Buesingen cars and motorcycles.
But since Buesigen has a special status even as far as car registration is concerned, the village was relieved from from the KN-obligations and got its own number plate with BUS-… initials.
To the advantage and ease of work of Swiss customs officials. While German cars are taxed as transient and most of the time aren’t even stopped, Swiss customs officials in Geneva or Basel know that cars with a BUS number plate belong to Swiss economic area and therefore could carry goods liable to customs duty. The Swiss customs official stops the BUS cars and asks the obligatory question: Have you bought anything or did you receive any gifts?
By the way, there are also cars in Buesingen that carry number plates with the initials BUS-Z. But there are very few of them. Cars who are importet to Buesingen with duty unpaid get this number plate, but they can be driven only for 2 years in this status.

Helpful for Swiss customs officials:
BUS-A…

And BUS-Z…