In Chicago where I live, we have lots of six-way intersections. That is, a North-South street, an East-West street, and a diagonal street that all cross at one point. I’ve noticed that at all such intersections, the green light moves counter-clockwise. That is to say, if the diagonal street is NW-SE, and the green light is currently on the N-S street, the green will next go to the NW-SE diagonal, then to the E-W street, then back to the N-S street again to start the cycle all over again.
(Obviously this would be a moot point at a normal, two-street intersection. Whichever street loses the green, there is only one other street for it to go to. But when three streets cross, someone has to decide where it goes next.)
Is this a universal rule? Granted, I haven’t surveyed every six-way intersection in Chicago, but enough to be pretty sure it is a rule here. Is it like that in other cities? In other countries? And if so, is there some sort of logic behind it that makes it a good idea? Something to do with driving on the right hand side of the road? Or is it just that it has to go in some direction, and CCW happened to get chosen?
Waiting left-turners have more time to clear the intersection if the progression is counterclockwise. That is, those southbound on Ashland, turning left to Lincoln, are less in the way of folks southeastbound on Lincoln than they would be of folks westbound on Belmont. (Theoretically, I know, since some left turns are forbidden at this intersection).
That’s a reasonable theory. If that’s the rationale, I wonder if the green travels clockwise in countries where they drive on the left. Any Jamaican’s or Limey’s reading this?
I’ve never seen such an intersection around here, so I have no idea how they would cycle. Diagonal running streets are fairly rare, and where one does pop up, it’s not intersecting at the same place where more perpendicular streets also meet. Sounds like really poor planning to set up the roads to make a 6 way intersection.
At least your intersections have an even number of streets crossing them. Racine WI has lots of 5-way intersections and other odd numbers, some of which feature a few one way roads, forks in the road (superimposed on an intersection), or underpasses with access only for southbound traffic. I’m told the roads were built on top of the old deer trails.
I do like the idea of rotating the lights such at the left turners get a little extra time to clear the intersection. That makes good sense!
I can see where it might sound like a bad idea, but it is actually smarter than you might think. We have a few places where a diagonal street crosses NEAR to a major NS-EW intersection, but not QUITE at the same point. That causes a real cluster-fuck! If any Chicagoans are reading this, think back to your fond memories of Fullerton-Ashland-Clybourn or Fullerton-Damen-Elston. The diagonal misses the cross-hairs by twenty or thirty feet, and EVERYONE suffers through multiple light cycles trying to get on their merry way.
Limey here, and while we don’t tend to have 6-way intersections here (that I’ve come across anyway) we have a few staggered crossroads set out in such a way that you couldn’t just run alternating opposites because a lot of the traffic wants to turn right. In this case, the lights do run clockwise at all such junctions I’ve sat at long enough to notice.
In a lot of other countries (UK certainly) this situation would be covered by a roundabout. In heavy traffic conditions though even that would be traffic light controlled both on the entry and during the circulation. Light sequences on such junctions are now being controlled by fuzzy logic and take lots of different factors into consideration.
When you are on them it certainly* seems* like they are running in a clockwise sequence but then…so are you! I suspect the order is actually more complicated than that.