Plan approval is a formal administrative procedure for the binding official determination of a plan. It regulates all public-law relationships between the project sponsor and the parties affected by the plan. Without the plan approval, a large number of public law procedures would have to be carried out for larger projects, which would make efficient and consistent planning almost impossible.

Construction projects are generally approved by means of a zoning decision.

In particular, the construction and modification of mountain railroads, overhead power lines from 110 kV, airports and landing fields, gas supply lines over 300 mm, dike construction and waterway expansion, railroad lines, federal and state roads, and highways are generally subject to plan approval.