Would you like to permanently use a public road traffic area above or below ground?
Then you need a corresponding permit or authorization.

In contrast to a special use permit, the permit authorizes the use of municipal land that does not impair the so-called public use of this land. This applies not only to permanent but also to temporary uses, e.g. as part of a construction project. Even if a building permit or another permit under public law already exists, this alone does not authorize the use of such land within the scope of the planned construction project.

Unfortunately this specification of service has not yet been completely translated.