The Wikipedia article on traffic lights is surprisingly comprehensive and interesting.
Yeah, I just wasted 10 minutes reading it in preparation for writing this annotation.
I'd write more on the subject, but it turns out I already have.
2018-11-07 Rerun commentary: It's a well known cultural trait (or perhaps stereotype?) that Germans habitually wait for the pedestrian light to go green before crossing the road, even if there is no traffic and it's perfectly safe to cross against the red light. By the way, I'm not implying that this trait comes from the Nazis. You'll note that Haken is the one who impatiently wants to cross, and Erwin - who is not your regulation Nazi by any stretch - is the one who insists they wait. The street, by the way, has a weird crack in it because the street plate comes from the LEGO Studios Steven Spielberg Movie Maker set, in which it is designed to come apart during some sort of disaster or monster attack to reveal red hot glowing lava beneath. Since as we all know, our roads are built right over molten lava.