It makes absolutely no sense. Every other city in this world except Calgary is able to build an interchange with sufficient on and off ramps. Is the point of an overpass not to rid the need of lights?
I recently did some looking around to see just when the Stoney Trial - Crowchild Trial Interchange would be complete. In doing so I also noticed that dispite a double overpass design, (PDF:
http://www.infratrans.gov.ab.ca/INFT.../stcrow-m2.pdf )
it seems city planners have decided a viable solution to move traffic faster down crowchild trial would be to trade in one set of lights for 2!
Now I know that the time a car will wait at each light is not as long as it would be without an overpass, and I also know that in the long term they plan to build the interchange in full with the proper on and off ramps. But come on, why built a road then change it in five to ten years?
That isn't the only example I could have used...as every other interchange being built over crowchild also has traffic lights...as do lots of others in the city, some of which are acceptable.
City planners in this city truly amaze me, so I suppose I thank them for that.