I-39/I-90 study in southern Wisconsin

Started by Revive 755, June 18, 2011, 11:55:07 PM

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triplemultiplex

Quote from: paulthemapguy on July 12, 2016, 08:57:33 PM
Hey, help a poor FIB out...When you talk about a reconstruction of the 39/90 and 12/18 interchange, does that include any realignment of the ramps?  Or just a replacement of the roadbeds (i.e. dig it out and put it back)?
WisDOT's latest preferred alternative is a massive rebuild into a turbine interchange with all exits and entrances on the right and some ramp braiding between the system interchange and Stoughton Road (US 51).
"That's just like... your opinion, man."


SEWIGuy

Quote from: paulthemapguy on July 12, 2016, 08:57:33 PM
Hey, help a poor FIB out...When you talk about a reconstruction of the 39/90 and 12/18 interchange, does that include any realignment of the ramps?  Or just a replacement of the roadbeds (i.e. dig it out and put it back)?


It would be a complete interchange redesign which would likely move the left exits to the right.

WarrenWallace

I hate sprawl!

on_wisconsin

Unfortunately, the state will probably go with A-1 or (more likely) F, given the current budget crap going on within the DOT.
"Speed does not kill, suddenly becoming stationary... that's what gets you" - Jeremy Clarkson

JREwing78

Strictly speaking, the only thing that WisDOT really has to do at the Beltline interchange is tie the leftmost lane of I-39/90 northbound into the left exit at the Beltline, and transition the onramp from the eastbound Beltline into the far right lane on southbound I-39/90.

There are compelling reasons to ditch the left exits. But this interchange isn't going to make or break the I-39/90 upgrades.

Say they wanted to punch a 3-lane mainline through this interchange. The major piece - the new NBD carriageway, can be done outside of the other changes to the interchange. Adding a third lane to southbound I-39/90 through here is likewise a simple undertaking. They can do it anytime.

If this is the piece that doesn't happen until 2022 or later, that's fine. Not doing this interchange right now is not a showstopper.

SEWIGuy

Unless I am mistaken, every alternative gets rid of the sole remaining left hand exit (I-39/90 North to US-12/18 West).  The only problem with some of the alternatives is that the cloverleaf exits remain from I-39/90 South to US-12/18 West, and US-12/18 East to I-39/90 South.

Those cloverleafs are not ideal.  However they aren't horrendous.

dfwmapper

E-1 and F maintain a left exit for the EB to NB movement. All alternatives eliminate weaving on the I-39/90 mainline, which is the important thing. D-1 seems like the best all-around option to me, keeping a loop for the movement almost no one is going to use, eliminating all left exits, eliminating all weaving, and still keeping a two-level design to keep the cost down.

triplemultiplex

Big fan of alt E1; at least half the EB traffic on the beltline is heading north on 39/90 so that is a situation where a left diverging ramp is called for.

Alt F is not going to happen, I predict, because it needs a shit ton of new r/w for an interchange with an already enormous footprint.

All of the options eliminate the left exit NB on 39/90 which is great.
All of the options add a SB c/d lane for the loop ramps (except for the one that adds a turbine ramp SB->EB, naturally); also great.
The ramp braiding between the Beltline interchange and Stoughton Rd seems like a good idea, though I personally have not had much trouble with weaving traffic there.  But I'm never traveling that way during morning rush and I'm usually coming from the north and then exiting the Beltline right away at Stoughton Rd or Monona Dr, so I don't really have to change lanes.
"That's just like... your opinion, man."



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