Interesting article.
It’s sometimes a placebo, but often still real, depending where you are in the world :)
The crossing pictured in the anime seems the kind most likely to be real, incidentally - a crossing on a straight stretch of road that isn’t at an intersection. There are several of these near where I live, and they’ll stay red all day long if nobody pushes the button.
The ones near me are especially satiafying to use, too. Because they don’t have to wait for an intersection sequence the light changes almost immediately when you push the button (if nobody else has recently pushed it) so it feels very powerful haha.
The amount of spam you get must be unreal