The cap seems like a good idea. Are there any other freeway segments in the Pittsburgh area where a similar cap could possibly be constructed?
Over the bathtub section of I-376 westbound and the 10th Street Bypass, but I don't know there's a lot of development potential for those locations.
The Bathtub I-376 might be possible, but then again, you have all those left exits/entrances in that area.

As for the 10th Street Bypass, yeah, no there, as they do already have a trail right along the river beside the road. Would have to remove that trail for the supports and I don't think that would be worth it.