Sorry for the double post, but it seems the Cline Ave bridge will be rebuilt as a private toll bridge. The consortium is led by FIGG Engineering, which designs largely concrete box girder bridges, including numerous cold-climate ones in the Northeast and Minnesota (e.g. the new I-35W bridge). So it looks like the Chicago region will be getting one new box girder, even if it's just a replacement of an old one.

Okay, enough with my obsession. :haha:

Really? You'd raise the Eisenhower up to surface level and put Halsted between UIC and Greektown into a tunnel just to get. . . what, exactly? Box girders for the Circle ramps? I'm of the opinion that the interchange should be subjugated to the city, and the surrounding streets should be as ped-friendly as possible. Having all the ramps pass beneath Van Buren, Halsted, and Harrison helps a lot.

I talked to one of the engineers at the meeting about IDOT's refusal to do box girders, and mentioned Ontario as the single exception. "Oh," he exclaimed. "That's already set for replacement."

How far down could you excavate before hitting water that would make digging deeper economically unfeasible? If you could get 90/94 twenty or so meters deeper than it is now(would obviously necessitate incline reconstruction N and S of interchange) you could hypothetically stack everything under street level and potentially deck over all or a portion of the interchange...

^ You can't really put 90/94 lower because of the Blue Line tunnel. Changing the alignment of the subway is probably so impractical it shouldn't be considered.

Mr D, I didn't mean "tunnel" literally. Halsted and Peoria would simply run beneath a 290 viaduct, like Desplaines currently does, but with better design and increased pedestrian space. Virtually all of the alternatives IDOT posted would require flyovers to pass above the Halsted and Harrison bridges, so we're already talking about ramps one or two levels above Halsted, no? Alt. 2-5 seem to demand it, and Alt. 1 is a relatively minor tweak.

I don't think it's possible to design a fully directional interchange in the footprint of the Circle without either keeping the current configuration, or going onto higher levels with long approaches. I'd need to see the traffic data, but I would almost lean towards an interchange that's non-directional, i.e. some ramps would be eliminated to make room for others. Is it reasonable to eliminate all access to Congress from 90/94, where drivers have lots of other choices for Loop access? Congress through the Post Office would then be accessible only to drivers from the Ike.

Oh jeez, I didn't even think of the Blue Line.

How far below the lowest point of 90/94 is the tunnel? How impractical would it be to go below that level with roadway?

The lack of overpasses over Halsted and Van Buren is why I feel that Alternative 1 is the best compromise. How much speed do we really need to build for in a location where the cityscape should be primary? I certainly don't consider Desplaines an example to be emulated.

We really should have built the Crosstown so every truck in the Midwest didn't have to go through here.

I believe the expressway is at -2 CCD where it passes under Halsted. At the midpoint of the Circle, the Blue Line tunnel is probably at -30.

I'm cool with a modest tweak like Alt. 1. More money for other vital road projects in the city, like new river bridges or auxiliary lanes on the Edens. I mentioned on the previous page that a modest redesign should be combined with a strong design and landscape strategy. That Irish project is a great example.

The ramp feeding southbound (officially, eastbound) I-90/94? This is already in need of replacement? Is this a capacity issue? If so, are there enough lanes in the downtown trench to accommodate the added flow (or is the real bottleneck the Circle, which will soon be alleviated)?

Talk about the Crosstown perked up a year or two ago briefly, in the form of a premium toll road (truck-caliber rates, which I assume they would be delighted to receive from rushing limos and luxury car drivers too). Is this still in the realm of possibility?

I was thinking that an initial leg connecting the Eisenhower and the Stevenson could be built in advance of I-290 reconstruction, to serve as a thru-traffic bypass for the eastern half of the reconstruction project. It's a modest 3 or 4 miles and presumably there are only large commercial landowners and very few NIMBYs. They could even get away with initially building just half of the lanes of the Crosstown (which I assume in total would be minimum 2 + 2 lanes plus shoulders?) if they were able to limit the Ike's lane closures to just the inbound or the outbound side at any given time.

In fact, nicely tying the Ike and Circle Interchange subjects together, could a Crosstown fully extending between the Ike and the Dan Ryan help lessen the design size of the Circle Interchange? This helps emphasize that the Crosstown could solve multiple problems.

CHGO TRIB - CTA's crowding-reduction strategy blasted at public hearing
 

By Jon Hilkevitch
Tribune reporter
8:04 p.m. CDT, September 4, 2012

Complete story at the Tribune website.

It is also worth bringing up the proposed service improvements (i.e. routes proposed to see more service), with some detail given here on slide 9-10:
http://www.transitchicago.com/assets...AL_090412s.pdf

In addition to the peak additions throughout the system, there are also some pretty substantial off-peak frequency improvements proposed for rail, especially on Saturdays, which more than restores the cuts made in 2010 which resulted in fairly infrequent off-peak service throughout the system.

Those are substantial off-peak improvements, particularly the Blue Line Sunday times.

And create a whole slew more.

Farewell, Goose Island Express... I barely knew ye.

Seriously, I had no idea this route existed. I dunno the frequency, but it would have come in handy on numerous occasions.

The loss of the Lincoln bus is also a crying shame. It's not prudent to axe bus service on a thriving pedestrian oriented commercial corridor. Maybe the employees can still get to work by walking from the Brown Line, but what about the customers?

Kind of sucks on the Lincoln Line, but it never seemed that much crowded. Any time I went to any businesses on Lincoln I forced myself to take the train despite that the Lincoln bus may be a more efficient alternative.

I remember when I discovered the Goose Island express biking around there. I seriously thought it was made up. Loaded the route on my phone and laughed how pointless it seemed. Great if you work for Wrigley, but they'd be better with their own private shuttles that could possibly be shared among other businesses and condos....kind of like 600 West shuttles. The city might want to figure that out. The increased passenger load on North and Division buses might work against their plan to de-crowd during afternoon commutes.

I wish I would have attended the Circle Interchange meeting. A few colleagues of mine thought about going.

If I were to apply my own imaginary design, it probably be very high level so you wouldn't have to acquire nearby properties. I'd achieve the greatest radius possible, with the straightest approach possible. Ideally, you try to limit the curves and in the past structural limitations have been in the inhibiting factors of creating more graceful turns...this should no longer be a problem. This means the flyover would initially cross overhead at a very shallow angle in relationship to the freeway below before making a turn.

My design would be loaded with integral straddle piers to accomplish the stacked approaches with lower deck to deck heights while maintaining high clearances. It would be steel box girders to ease the construction complexities of a unique design. Something like the spans in the link below.

http://goo.gl/maps/b7htk

In a nutshell, all ramps would do their best to cross over existing freeway through lanes in the shallowest ways possible. This means approaches would extend further in all direction and would require careful negotiation around nearby exits. It also means increased structural complexity with stacking flyovers traveling above thru lanes at very acute angles. We already have something to look at here locally, but far less elegant. Notice the non-integral piers.
http://goo.gl/maps/kKXdC

^ Cool Houston example, avoids the unsightly straddle bents with a cantilever.

https://maps.google.com/maps?q=houst...79.78,,0,-5.78

Did you look at the five alternatives?

A high stack might well move the most vehicles through per hour, but it's certainly not the best thing for a cityscape with pedestrians.

What customers?

Ridership on the 11 had a weekday ridership average last year of about 5,600 people. Ashland had 29,000, Clark 22,000, Milwaukee 11,000, Archer 12,000. Grand, 8,000. Belmont, 22,000, Diversey, 11,000. Those are routes from the area or a few with similar characteristics.

There are 131 routes tracked by the CTA. Average weekday bus ridership was about 985,000 people last year. That means the average bus route has about 7,500 riders on a weekday. But it's worse than that, because 14 of those routes report less than 500 riders per weekday because they're specialty stuff that doesn't compare to normal routes. If you remove those and 7,000 daily riders, the average bus route has about 8,300 riders per day, and if you basically clean up the stats and discount all specialty routes and private-subsidy routes, you end up with an average for "normal" bus routes of nearly 9,500 riders per weekday. That's a lot higher than Lincoln, and Lincoln is a long route - about 12 miles, which is longer than almost all east-west routes, and is even 80% as long as the long 49/Western route.

From an hours perspective, it runs similar hours as the 157 route - which is half as long and doesn't run at all on the weekends. The 157 gets about 5,400 riders per weekday. So the riders per mile per hour is about twice as high as the 11.

Riders per hour per mile (bi-directional, so double the length of the route) I indicated Night Owl routes just to show their averages are probably lowered by lower overnight ridership:
22/Clark: 45 (Night Owl)
157/Taylor: 37
56/Milwaukee: 30
9/Ashland: 35 (Night Owl)
62/Archer: 22 (Night Owl)

11/Lincoln: 19

And compare that to a rush-hour-only express bus downtown:
125/Water Tower Express: 60