Dallas - Fort Worth: I-635 toll lanes

[mightyace]

Cintra, Meridiam, Dallas cops/fire pension concessionaire for TX/I-635 toll lanes

http://www.tollroadsnews.com/node/4035

These are additional lanes.

[Greybear]

Should be interesting. I-635 (LBJ Freeway) across North Dallas has always been one huge bottleneck for years. Let's hope this helps.

[Chris]

Interesting plan, you don't see a depressed tollway with freeway lanes on top of them often. But I think the construction costs are fairly high, aren't elevated tollway lanes cheaper?

[mightyace]

Interesting plan, you don't see a depressed tollway with freeway lanes on top of them often. But I think the construction costs are fairly high, aren't elevated tollway lanes cheaper?

Maybe, but I'd guess maintenance would be lower as you have less roadway that is exposed to the air on the bottom plus the ground is supporting the upper (freeway) lanes instead of concrete posts.  And, that's important as it can still get cold in Dallas/Fort Worth.

[Gridlock]

Originially the HOT lanes were to be in tunnels, but this modified setup is to save costs.  They had an environmental mandate not to make the ROW wider nor the visual impact taller, thus elevated lanes were not considered.

This set up is also supposedly quicker and less disruptive to construct than the other scenarios.

This cantilevered approach is already used on US 75 in Dallas where the feeder roads are partially over the mainlane trench due to ROW constraints.

[J N Winkler]

The most ambitious concept studied (several years ago) was to have the toll lanes in a twin-bore tunnel, which would have had bored and cut-and-cover sections, with the bored sections in limestone a good way beneath the freeway.  But there were concerns about ventilation, which would likely have required the tunnels to be air-conditioned (!) in the summer, as well as certain types of rock at the likely levels of the tunnel which tend to expand when they absorb water and would therefore have placed pressure on the tunnel wall.

TollRoadsNews has the details on the Cintra et al. proposal, which is what was eventually chosen, but I have seen the schematics for Dragados' proposal.  It called for everything to be at surface level except for the eastbound HOT lanes, which were to be immediately beneath the eastbound general-purpose lanes.  It would not have been even a cut-and-cover arrangement--my guess is that the eastbound GP lanes would have been suspended on transverse girders over the HOT lanes.  The design didn't go into any detail about ventilation arrangements.  Conceptual guide signing plans were available, however, and these showed that the tunnels would have had horizontal-format guide signs, similar to what is used in the Big Dig to accommodate low ceilings.

[mightyace]

It looks like the concession on the express toll lanes is close to a done deal.

TxDOT, Cintra close on N Tarrant Express concession in Dallas

[travelinmiles]

That's an incredibly inaccurate article.  North Tarrant Express refers to I-820 and SH 121/183 in northeast Fort Worth and its northeast surburbs, as well as I-35W in North Fort Worth.  I think the article is referering to the "DFW Connector" or "the Funnel which is where 121/183/26/360/1709/2249 and I-635 meet north and west of the airport.

[mightyace]

That's an incredibly inaccurate article.  North Tarrant Express refers to I-820 and SH 121/183 in northeast Fort Worth and its northeast surburbs, as well as I-35W in North Fort Worth.  I think the article is referering to the "DFW Connector" or "the Funnel which is where 121/183/26/360/1709/2249 and I-635 meet north and west of the airport.

Looks like you're right.  This article is a followup to

http://www.tollroadsnews.com/node/4035

so I think I-635 is the right road as mentioned in the orignal article but the current article got it wrong