[biketrouble]

The problem with just using that space for non-residential uses like you suggest is that they become dead zones at night. To build a livable urban fabric I believe you need a mixture of uses, residential next to commercial etc. That way, you get "eyes on the street". If you just build commercial there, or put in a streetcar OMC or above ground parking or whatever, you're just compounding the original problem.

So this is the problem with the viaducts, basically they are a constraint that makes it harder to build this kind of mixed usage development.

I thought it was pretty obvious that I disagreed with your suggested approach from my response to Deasine's OMC proposal, didn't see any need to repeat myself.