Quote:
Originally Posted by Innsertnamehere
I believe the only 4 stack in Canada is the 400/407 in Vaughan. Might be wrong though.
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It is.
I find the word "stack" get used pretty loosely nowadays and gets applied to any kind of "spaghetti" interchange with multiple levels of ramps.
Traditionally, the term "stack interchange" denotes a 4-level interchange where all movements are facilitated by directional ramps (not loops) that exit and merge on the right and cross in a symmetrical way like this:
The ramps usually cross at the same point giving it a layered appearance (freeway, freeway, left turning traffic, left turning traffic), i.e. the ramps are "stacked", hence the name. Some stacks have additional HOV ramps and frontage road levels added as well but they all have that same basic topology.
The 407/427, 407/410 and 407/404 interchanges don't meet that definition (technically they are "cloverstacks", combinations of stacks and cloverleafs, but they are designed to be easily modified into stacks), neither does the Turcot interchange but you could make an argument that the BC99/Stevenson interchange sort of does. Of course it's obviously not a true stack (it's only three levels and the directions of traffic reverse on Stevenson) but you could argue that it's design reflects the "spirit" of a stack: it has symmetrical directional ramps for all movements and if you look at the aerial view, you can see that distinctive shape of a stack. The fact that they managed to do it with one few level is what makes it interesting to me. It's a new twist on an old design and a clever idea. Whether it will drive well, I can't say.
But that's what I was talking about when I said it could be argued to be Canada's second stack. Maybe I'm the only one that had that thought? It's the kind of ridiculous hair-splitting only a hardcore roadgeek would ever bother to engage in.
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