> Except you cannot have static signs from one direction, where the other directions have traffic signals.

I don't know about such a rule. There are some intersections in Germany where there are red and orange lights, but no green for e.g. just one direction. At such a place, when no light is on, rules according to the static signs apply, while other directions still show some light. So what you're saying doesn't hold at least temporarily there.

> This solution is neat

I don't think so. Someone unfamiliar with the place might think the light will turn eventually green, even if it's unclear where one could go if it did. It will at least cause confusion and unnecessarily draw attention away from actual traffic. And of course there's the maintenance and power cost.

Until an attacker comes and "parks" in front of the red light blocking all the traffic. There is no legal obligation to keep moving.

The law tends to address this in various ways. I don't know how German law does it, but usually there is a fairly exact description of what stopping for a traffic signal entails (e.g., the driver has to be present in the vehicle). Also most jurisdictions have a catch-all law that prohibits dangerous behaviour in traffic.

So yes, there probably is a legal obligation to keep moving. If you went there and stood in front of the light for an hour a friendly but stern police officer will — legally, and within his mandate — instruct you to move along.

There is, though. General red with a specific green (the arrow pointing to the right) means you can stop, but once a car behind you wants to turn right, you need to turn right too in order to keep traffic flowing.

The charge is usually "public nuisance" or the local jurisdictional equivalent.

In case anyone is unfamiliar with the concept of public nuisance as a crime. It's pretty simple, "things that cause significant enough trouble for other people". Its the common sense escape hatch option for law enforcement being unable to see any other crime.

I would guess that it would be "Behinderung des Straßenverkehrs" (obstruction of traffic).

They could solve this problem by turning it green every now and then, though.