In the case of the Crowchild and Stoney Trail plans, I would say lights on Crowchild are in fact safer than loops. Often loops are not an option due to a lack of space either due to topography or development. In this case I would say it was a matter of safety and cost. Loops are pricier, and having loops coming off of Stoney onto Crowchild (aka. the Parclo B loop) would be unsafe because having a high-speed traffic slow down to come onto a loop can cause roll-overs.
Actually what they have shown for the ultimate design is interesting in the fact that they do have loops to eventually accommodate free-flow left-turns in the future as shown by those orange loops. And they've managed to get rid of the Parclo B loops by looping them off the ramps instead, which seems like not a bad idea.
And yah like Snakeeye says, not every road intersecting on an interchange has to be free-flow. In this case only Stoney is designated as such in the first stage.
I do agree though that there are some pretty bad designs for Stoney out there that are floating around!
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