Once you start thinking about using one-way operation as a framework for capacity expansion you immediately look at IH 10. There’s not a lot of extra room in the existing ROW. It’s got the tightest mainline corner in the Downtown Loop. Sight distance is less than awesome. And there’s a lot of vacant land to the north that makes an ideal place for a freeway. So what could you do?
The simplest thing to do is retain the geometry of the existing 10-59 interchange and start the shift west of Elysian:
This takes out Reader’s Wholesale, which is kind of a dick move. It’s a cool building, it’s a going industrial concern, and said building was built by said industrial concern. When you consider the kind of stuff that holds up projects elsewhere (e.g. junkyard owner wants to sell to the DOT, but can’t because the junkyard was the site of a brewery 100 years ago), it shouldn’t be too hard to avoid this. A more context-sensitive alignment might shift the “Freight Main” to the north.
This is basically “threading the needle” in that you’re putting lanes through the vacant lots while preserving almost all the existing buildings. You also have the option of depressing the entire facility below grade. When IH 10 was built it had to go up and over the M-K-T which also meant overpassing Main and San Jac. But since that’s now the Heights Bike Trail, you could lower IH 10 and send the bikes over the top of it.
The downside to this is that the new alignment is only mildly less curvaceous than the old one, particularly where you have to thread IH 10 around the freight main bridge over White Oak. A more radical option is to abandon the freight main entirely and replace it with a three-track passenger main, possibly using some of the right of way of the old IH 10.
I’m not sure I’d personally go this route, but it could be done.