The one thing I don't like about signals being placed before the intersection is that it can be hard to see the signal if you're the first car at the intersection imho, over here our signals are arm mounted after the intersection, one on each side.
I've seen signals mounted before the intersection here too though in conjunction with the regular signals. They're used where the sightlines approaching the intersection might be poor.
I've never seen a four way signal here in Ontario even in pics from the '60s though. Maybe they used them at one point...
Joseph, btw, i noted yesterday (Saturday feb.6.2011) that the traffic lights in Israel, arranged in a different way from what i thought before: In many of the juctions and the pedestrian crossings with traffic lights in Israel, the traffic lights actually stands on BOTH before and after the junctions or the pedestrian crossings.
I saw this firstly on Saturday feb.6.2011 in Haifa.
Anyway, i found several examples of this arrangements in pictures on my traffic lights and signs album in my gallery on this site, and
here is one of them: In this case, in this Emeq Hefer settlements junction picture, you can see four traffic lights, while each couple traffic lights is for the same direction, in each couple, one traffic light is far from the driver then the other.
The close traffic lights located BEFORE the junction and the farther traffic lights located AFTER the junction.
In pedestrian crossings with traffic lights, the traffic lights arranged in the same manner.