Winnipeg | Perimeter Highway

[biguc]

Exiting cars slowing down share a lane with entering cars speeding up. I guess you could eliminate it by having exit lanes pass under entering leafs, but then you have to make extra bridges for each leaf, and main bridge wider, and probably the entire thing bigger. At a certain point you may as well make a stack.

I'm not sure I see much of a case for cloverleafs. If you have two free-flowing highways intersecting, build a stack. If you have a non-free-flowing road (a la St Mary's) intersecting with a highway, just make a diamond.