[prance]

> 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.