Lowering the curb with barriers in NRW - How to invoice?

Hello everyone,

We own a two-family house with a driveway with a garage and two parking spaces. Now, the parking situation on our street is quite poor or, basically, parking is not allowed at all because otherwise the sidewalk would be blocked or the street would become too narrow. In terms of space, we have the possibility to create two more parking spaces on the other side of the house. However, these parking spaces cannot be reached through the already developed driveway, so I would like to lower about 6 meters of curb for these parking spaces. Parking space in the public area would not be affected because there is no sidewalk on this side anyway. Today I spoke with the person in charge at the building authority and he said that my house is already developed and a further curb lowering would only be possible if I were to put a garage there. That does not seem rationally thought through to me. Does anyone have knowledge of the regulations? What loopholes are there? I have already thought about converting an existing chicken coop 2.40x2.40x2.0 into a garage in order to achieve a curb lowering. Is something like that possible? Are there minimum size requirements for garages? I thank you for your input.

Who is supposed to pay for the reduction and any resulting consequential costs?

Well, me! It's only about the approval

Have you also ever brought up the finances? Like that the community doesn’t have to pay? Maybe that will help.

Of course! That was not up for debate at all and was defined in advance that these costs/risks naturally transfer to the applicant.

That doesn't sound rationally thought out to me.

Not to me either. Either there is a statute that prohibits a second access, in which case a garage doesn't help, or there are no local building regulations, then I see no reason for rejection.
Which building authority did you call, the building regulations office or the civil engineering office? Since parking spaces up to 100m² are exempt from approval, the building regulations office actually has nothing to do with it. Try a different caseworker or the other office and have them explain on what legal basis this statement is made if rejected. Also, two houses down there is a second access without a garage.