Never ever seen an emergency vehicle getting stuck on the viaducts, especially since the Georgia viaduct never gets congested! Therefore I'm not sure who first spread the rumour without any basis. If there is a congestion on the Dunsmuir viaduct coming into downtown, an ambulance can simply take an alternate route by going on the Pacific Boulevard. If the viaducts are gone, there won't be such a choice.
For the person who says that traffic planners know best: Explain the congestions along Seymour nowadays when there used to be hardly any back when more of the downtown streets had more travelling lanes. Do they really know better?
As for earthquake dangers, simple answer is to spend the money to upgrade these vital urban infrastructure: way cheaper than taking them down.
Again who are we kidding about the viaduct removal? Word it that the City still doesn't have the money to do so.
Proposed in 2015 and still not happening....
http://www.vancouversun.com/vancouver+un...ia+dunsmuir+viaducts/11418320/story.html