[hulitu]

> The order of the lights doesn't change.

For 3 lights streetlights no. For 2 lights streetlights it depends. They can be (in DE) either red and yellow or yellow or green.

[iggldiggl]

AFAIK yellow + green is only ever used for turning traffic and is always installed together with a regular 3-bulb traffic light for the other directions. Stand-alone two-bulb traffic lights are always red + yellow, with red on top, just as usual.