Scoping study for fixing Chicago's Circle Interchange

[Revive 755]

http://www.dot.state.il.us/ptb/PTB%20163/D1/Circle%20Interchange%20-%20Geometrics%20Unit%27s%20Scoping%20Report,%20October%202011.pdf

[Jordanah1]

why not a stack interchange there? it would still be slow, but faster than it currently is.

[Brandon]

why not a stack interchange there? it would still be slow, but faster than it currently is.

There's no real space for a full four level stack there.  You have the four streets that constrain the interchange, and they really cannot be blocked off.

[Jordanah1]

im not saying 70MPH ramps here, i think 45-55MPH ramps can be built for all of the left turns (accept mabey the West>South movement. and a four (five with the surface streets crossing on their own grades)-level stack would be able to be built so that the ramps are over the current streets, rather than smushed in-between them, giving more room to work.

[colinstu]

im not saying 70MPH ramps here, i think 45-55MPH ramps can be built for all of the left turns (accept mabey the West>South movement. and a four (five with the surface streets crossing on their own grades)-level stack would be able to be built so that the ramps are over the current streets, rather than smushed in-between them, giving more room to work.

I've tried designing four level and modified stacks before in this area before for fun... it simply wouldn't work in my opinion after hours of mulling around with what can be done. It's a really small area, and really constrained, among other things. Removing a good chunk of surrounding surface street/grid would help, but would create all kinds of other problems and is out of the question.

I hope they go all out with Concept B. It's not gonna 100% fix the problem (I'd have doubts of it even getting 75% better. but this doesn't mean they shouldn't do it or anything), but $300-400m looks like pennies compared to the interchange projects Wisconsin has been/will be having. It's worth it.

I already see some problems with the Concepts. Seriously... I90/94 NB to I290 WB... look at that ramp. Big on capacity, but it merges down to 1 lane last second. That's gonna be rough IMO. At least IDOT is getting serious about fixing this interchange... it really sucks. I can't wait for things to move forward.

[froggie]

im not saying 70MPH ramps here, i think 45-55MPH ramps can be built for all of the left turns

If it were to be rebuilt as a stack and given the space constraints, the *BEST* you can hope for is about 30 MPH ramps.

[hobsini2]

That's why I would leave it as it is. The only way you could get a stack to fit in that tight space would be to close Harrison and Van Buren which is very unlikely to ever happen esp for Harrison due to the traffic at UIC and it being the farthest south bridge over the Chicago River until Roosevelt Rd.

[Revive 755]

Public meeting on August 30 for the Circle interchange:
http://www.dot.il.gov/press/8%2016%2012%20Circle%20Interchange%20Public%20Meeting.pdf

[Henry]

Looks like the $375 million project is about to begin:
http://www.chicagotribune.com/news/local/ct-met-circle-interchange-0831-20120831,0,2300573.story?track=rss

[colinstu]

Looks like the $375 million project is about to begin:
http://www.chicagotribune.com/news/local/ct-met-circle-interchange-0831-20120831,0,2300573.story?track=rss

Awesome news!!

[Mr Downtown]

Following an open house on August 31, Illinois DOT has released the various alternatives for reconstruction of the Chicago Circle Interchange.  PDF here.

Of course, the project isn't funded yet, so no one can predict when this might happen.  IDOT is mainly concerned about improving the throughput/reducing the backups on north-to-west and east-to-north movements, so at a minimum the alternatives give two lanes for both those ramps.  Most of the alternatives also make the Dan Ryan four lanes all the way through (rather than the current three) and some push five lanes through.

One funny thing is that they haven't yet sketched out the vertical dimensions, and some of the alternatives create nearly complete Texas-style stack interchanges that would rise 50 feet or more above the surrounding streets.  I'm certainly not crazy about that because of the impact on the pedestrian environment and cityscape, and I think the speed gained by smoothing out the curves will be largely defeated (especially for trucks) by the elevation change required.  With mainline approach speeds of 45 mph or less on all four sides, I'm not sure what's really gained by allowing all the Circle ramps to be traversed at high speeds.

All the alternatives push the decision points, gores, and merge points further away from the Circle itself.  Some show six westbound lanes leaving the Circle on I-290; the idea is that lanes would drop at Ashland and somewhere else (undecided) just west.  There's been some talk about whether the Morgan exit should be retained, especially now that the Univ of Illinois at Chicago has closed that street south of Harrison.

Another curious thing is that IDOT just did a master plan for the interchange's hardscape and landscape in 2010 (PDF here) but there's been no mention of that plan in these meetings, and that plan didn't say anything about expansion or reconfiguration.

As a freeway historian, I'm reluctant to see the Circle's historic unique design completely blown away, but I think that will be a hard argument to make to the folks in charge of this.

[Alps]

As a freeway historian, I'm reluctant to see the Circle's historic unique design completely blown away, but I think that will be a hard argument to make to the folks in charge of this.

There's always Albany.

[Revive 755]

A preferred alternative seems to have been picked; see Page 59/76 and Page 73/76 of http://www.circleinterchange.org/pdf/document_library/circle%20pwg3%20ppt%20for%20web.pdf