I'm not sure how a freeway would play out at the north end, though; for example, redevelopment ("site vision" here) between Mississippi and I-25 picture new accesses at the grid positions of Kentucky (full movement with a bridge over the Platte) and Tennessee (RIRO). North of Florida Ave is the busiest section, though.
Can't the issues toward the north end (for instance the intersections at Mississippi & Florida) be solved by adding frontage roads (maybe Platte River Dr can be extended north--it would still provide access to Florida) with slip ramps for Mississippi?
Could you describe what you’re picturing a bit more? I don’t know if I’m thinking of the right part of Platte River Drive. In any case, I bet you’re right that they could work out a frontage road setup in that area, but I don’t know if CDOT would want to attempt it, particularly if Denver or the adjacent landowners weren’t on board. With traffic levels so high, though, there could be a higher chance that they'd give it a try, maybe?
Somewhat on that subject, I was trying to see if I could get the transportation plan or review comments for the development north of Mississippi. I found
a page for it (or close to it) on Denver's website, but no actual documents. I'm not sure if I'm looking in the wrong place, bad at finding links, or if they just don't post those things publicly.
I wonder that if/when this Santa Fe conversion happens would they change the Rush Hour HOV lanes into 24/7 HOT lanes?
It seems like they’re still contemplating what future lanes will look like; on the
PEL meeting site zzcarp linked, the "Level 1 Selected Concepts" slide has potential recommendations grouped by type, with lane modifications mostly in "Cross sections."
Concepts with managed lanes—which I’d certainly expect to stick around—picture "enhanced managed lanes" with "enhanced manage lane technology and dynamic signage" that sounds like other CDOT express lanes. If they went with the freeway option, I’d tend to think the HOV lanes would become full HOT lanes; they might do that anyway, though. (Diagonal Highway's getting HOT lanes at some point, so they wouldn't be alone here.)