Visibility triangles - What are the requirements in residential areas?

I have a quick question regarding the topic of visibility triangles, as I am no wiser even after extensive research. I do not want to inquire with the municipality / the responsible building authority initially (-> do not want to wake sleeping dogs).

In our development plan (building area in Lower Saxony), requirements for existing visibility triangles are defined in the textual provisions. Our property is located on a private road, of which we are partial owners (see sketch). This private road is not(!) included in the development plan. Accordingly, no visibility triangle is marked at the junction.

Our architect pointed out to us that the municipality can still demand such a free visibility triangle. I have now done extended research to better assess whether the municipality could really demand something like this from us. If so, (depending on the size) the terrace would be visible. For this reason, I have the following questions:

[*]On what legal basis (Lower Saxony) can visibility triangles be required?
[*]What do the corresponding regulations look like in residential areas – does Tempo 30 + right-before-left apply? (On one hand, I read that in such areas visibility triangles do not have to exist. On the other hand, I read that they just do not have to be marked in development plans)
[*]Do these regulations also apply to private roads?
[*]How large must such a triangle be if it were actually required from us?

I now know that this whole topic is a matter for the federal states and that often the guidelines for the design of urban roads are used. Nevertheless, I have not come to any real conclusion so far. I do not even know if our private road is considered a public road according to (§ 2, ...) NStrG. After all, this road basically only serves so that the respective residents can reach their properties.

Can someone help me and possibly has experience regarding this topic?

Many thanks in advance.

On what legal basis (Lower Saxony) can visibility triangles be demanded?

§20 (7), §31 (2) NStrG
Another possibility is a municipal ordinance.

What do the corresponding regulations look like in residential areas – does speed 30 + priority to the right apply?

You yourself write that this is described in the development plan. Otherwise, the road authority will name the required dimensions and refer to the corresponding RAS (Guidelines for the Design of Roads).

Do these regulations also apply to private roads?

Yes. see §20 (7) NStrG

How large must such a triangle be, if it should actually be required here?

see paragraph 2

I don’t even know if our private road is a public road according to (§ 2, ...) NStrG.

You can inquire with your municipality. If it is not a historical road (dedication in immemorial times), it is with very high probability not dedicated (§2 (1) and §6 (2) NStrG). But that does not matter. If the municipality sees a hazard here, you will probably have to take measures. As with any administrative act, of course you have the option to sue.

Can someone help me and possibly has experience regarding this topic?

There is already, almost still fresh, a discussion on a very similar question at: .

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