Honestly I think with the development and everything it would be very hard to widen I-94 in Ann Arbor between M-14 and US-23. A re-route of the highway might need to be done in order to do that.
A 6 to 8-lane fully Interstate-standard freeway needs, at a minimum:
10-foot outer shoulder
3-4 12-foot travel lanes
10 foot inner shoulder
12 feet in the median for bridge abutments, drainage, barrier, etc
10 foot inner shoulder
3-4 12-foot travel lanes
10 foot outer shoulder
Total minimum width: 124 feet for 6 lanes, 148 feet for 8 lanes
I-94 is sitting on 200' right-of-way. So even if they jam in 8 lanes through there, there's room. Even with 8 lanes, there's 26 feet on each side to install barriers, noise walls, and whatever else might be needed. If MDOT purchases additional right-of-way width, it's because it's cheaper to do so v.s. the cost to jam it into the 200' wide footprint.
The Lodge Freeway (M-10) squeezes a 6-lane freeway into a 100-foot wide footprint between the service drives. They cheat a little by cantilevering a few feet of guardrail and service drive over the freeway. But they can be forgiven - consider that those 6 lanes of freeway, full-width outer shoulders, 12 feet in the middle for bridge abutment, barrier, and lighting, 6 lanes of service drives, a few feet of grass strip, and outer sidewalks all fit into 200 feet of right-of-way.
By comparison, I-94 around Ann Arbor is a cakewalk - mainly suburban, and room for modest additional amounts of ROW without touching any buildings. It would certainly be easier if MDOT was working with 300 ' or 400' of ROW, but
The draft 2023-2027 Five-Year Plan is now available on MDOT's website. The only highlights for me are the 1-375 removal project that will begin in 2027 and the total reconstruction of U.S. 23 between I-94 and M-14, including replacing all the bridges along that stretch. I'm really hoping MDOT adds a third lane here because that stretch of U.S. 23 needs it.
https://www.michigan.gov/mdot/-/media/Project/Websites/MDOT/Programs/Planning/Five-Year-Transportation-Program/2023-2027-Draft-5YTP.pdf?rev=7be7999b307e4779a0aa4a9b8c2a80bd&hash=F042F924BA941C9D5B0C255B01212DCC
Pretty safe bet it's going to be at a minimum 6 lanes, and probably 8 between Washtenaw Ave and I-94. Unlike US-23 north of M-14, the overpasses are wide enough as they sit now to take 6 lanes. Even if that was a problem, they're replacing the bridges anyway, so there's no cost benefit to building a "Flex Lane". They *might* build the outer shoulder wide enough for Flex Lanes, but that'll be in addition to 6 full-time travel lanes.
The whole Flex Lane thing for north of M-14 was about buying time before having to completely replace the roadway from the ground up. As much as we despise the idea, it working well enough for MDOT to expand its use to other areas.
As pointed out earlier, MDOT is working with a limited budget that could easily be curtailed further out of political expediency. US-23 north of Ann Arbor is a busy roadway, yes, but there are freeways in Michigan that need widening more. I'd rather the money for widening got prioritized for things like I-94 (and it's > 10,000 commercial trucks per day) than for a roadway like US-23 that's mostly commuter traffic.