TXDot looking at sinking I-35 through downtown Austin

[longhorn]

Envision the sunkedn Woodall Freeway in Dallas with a park on top. May not solve.........no, will not solve bottleneck called I-35 through Austin, but it will look pretty.

http://impactnews.com/austin-metro/central-austin/civic-groups-back-i-35-cut-and-cap-proposal/

http://www.bizjournals.com/austin/blog/at-the-watercooler/2013/06/cut-and-cap-surfaces-again.html?page=all

[Chris]

I like the idea, but funding will be an issue. I also think they should not go forward with this unless I-35 has at least 10 through lanes. After all it will remain the most important freeway in the fastest growing large city in the U.S. It would be a waste of money to spend possibly over a billion dollars while not eliminating / significantly reducing congestion. If you do it, you got to do it right. There is no need for half-assed solutions.

When was that double-deck segment constructed? Will it need extensive renovation or replacement in the near future?

[longhorn]

I believe the I-35 split was built in the late 70s. When TXDot rebuilt I-35 from the 183 exit in North Austin to Sam Bass Road in RoundRock, in the 80s, it only added one lane each way to a four lane freeway. TXDot should have doubled the lanes from four to eight. I-35 begs for more lanes.

[Alps]

Cut and cover I-35 through Austin... with another I-35 on top. Problem solved.

[MaxConcrete]

When was that double-deck segment constructed? Will it need extensive renovation or replacement in the near future?

The opening date I have seen in press reports is 1975. I think it is still in good condition and has plenty of life remaining (20+ years) with minor maintenance.

[thisdj78]

Funding will continue to be the issue. There's other things that can be done to alleviate at least some of the local traffic:

1) Replace the remaining stop lights on 183 with overpasses (east of Austin)

2) Built direct connectors from 183 to Northbound 35 and from southbound 35 to 183.

this, along with the grade separation being added to 71/Riverside and 290 to SH130, could provide alternatives to folks using 35 for local trips.

[Henry]

I wouldn't be surprised if they looked to Boston for the blueprint!

[rte66man]

I wouldn't be surprised if they looked to Boston for the blueprint!

On how NOT to do it?

rte66man

[AustinRoads]

Hi.  I normally lurk but I thought I might chime in on the matter.

Never mentioned in this plans is a way to mitigate the following phenomenon, which would only get worse with this short tunnel.  These are the comments from a user who often comments on articles on the matter:

2. Exacerbate the "shock-wave" phenomena -- The vertical profile of the underground road lanes from its southern portal between the Colorado River and Holly Street and a northern portal between 15th Street and MLK Blvd. might be level 20-25 feet below nominal ground surface, but the transition approach areas must match to the existing road levels at the bridge and upper/lower deck split at each end, respectively. The northern transition required to do so will significantly increase the gradient which traffic in both directions must negotiate -- for heavily-loaded northbound trucks, the abrupt slowdown and slow recovery in speed at the existing north area produces a significant congestive effect, particularly during already-congested peak period traffic conditions, and an increase in the length and vertical elevation change with the added gradient would seriously impact performance and congestion even worse than now exists. For southbound trucks, vehicle braking performance and drivers' ability to see far enough ahead and quickly react to spillback of congestion within the tunnel against natural acceleration by gravity on the downgrade would have an increased risk with the higher and longer gradient.

A similar situation exists southbound with the climb out of the river valley.

Let us assume no work will be done on 183 (more on that in a minute).  I envision that for total relief of the congestion a six-mile long tunnel from 51st to Oltorf would be required.  I doubt that's feasible under any economic conditions.

Funding will continue to be the issue. There's other things that can be done to alleviate at least some of the local traffic:

1) Replace the remaining stop lights on 183 with overpasses (east of Austin)

2) Built direct connectors from 183 to Northbound 35 and from southbound 35 to 183.

this, along with the grade separation being added to 71/Riverside and 290 to SH130, could provide alternatives to folks using 35 for local trips.

1. There are plans to do this:  http://www.bergstromexpressway.com/multimedia/  It would be tolled, of course.

2. Its more feasible to complete the stack at 290/183 (the footings are already there) and tie that into the 290/35 interchange somehow which already has the movements missing at 183/35.  The businesses at the latter interchange are right up against it.

[Anthony_JK]

I suppose that this would make simply shifting I-35 to the TX 45 SE/TX 130 bypass route a more feasible option?? Especially if the tolls are removed and the roadway widened to 6 lanes??

[Sykotyk]

I suppose that this would make simply shifting I-35 to the TX 45 SE/TX 130 bypass route a more feasible option?? Especially if the tolls are removed and the roadway widened to 6 lanes??

As long as there's no frontage roads, I don't see TX130 necessarily needing additional lanes immediately if tolls are eliminated. The traffic is primarily through traffic. Traffic headed into or out of the city still relies heavily on current I-35. Keep the land available for eventual expansion (enough for 8 lanes, at least), but refuse frontage roads and allow it just at regular interchanges.

[texaskdog]

It's all because the people in economically poor East Austin feel "separated" because there is a freeway between them and downtown.  That is not the cause of their problems, and putting a $60 billion parkway in there is not going to fix that.

[texaskdog]

I suppose that this would make simply shifting I-35 to the TX 45 SE/TX 130 bypass route a more feasible option?? Especially if the tolls are removed and the roadway widened to 6 lanes??

As long as there's no frontage roads, I don't see TX130 necessarily needing additional lanes immediately if tolls are eliminated. The traffic is primarily through traffic. Traffic headed into or out of the city still relies heavily on current I-35. Keep the land available for eventual expansion (enough for 8 lanes, at least), but refuse frontage roads and allow it just at regular interchanges.

what's funny is if you're at the split in Georgetown, both 35 & 130 say "Austin".  Not a very practical way to go to Austin on 130.

[AustinRoads]

Northbound traffic would only be afforded single lane ramps departing/entering 35, so those ramps may need added capacity.

[thisdj78]

1. There are plans to do this:  http://www.bergstromexpressway.com/multimedia/  It would be tolled, of course.

2. Its more feasible to complete the stack at 290/183 (the footings are already there) and tie that into the 290/35 interchange somehow which already has the movements missing at 183/35.  The businesses at the latter interchange are right up against it.

As soon as I posted, I looked up and found the project site. Seems like it would be a quicker and cheaper alternative.

In regards to the 290/35 interchange, seems like the 183/35 would be a better bypass exit, considering that traffic starts to build up just south of there so by the time you get to 290/35, you're in it. If you look at an aerial of the 35N to 183N flyovers, they go right over the business properties (same with 1604/281 in San Antonio as well), so proximity to the frontage wouldn't be an issue.

[thisdj78]

Northbound traffic would only be afforded single lane ramps departing/entering 35, so those ramps may need added capacity.

True, but I imagine if 35 were to ever be moved to 130, it would continue to Seguin which has two lane ramps.

[Anthony_JK]

Northbound traffic would only be afforded single lane ramps departing/entering 35, so those ramps may need added capacity.

True, but I imagine if 35 were to ever be moved to 130, it would continue to Seguin which has two lane ramps.

More likely, I-35 would be rerouted via SH 45SE to return to the original I-35 just south of Austin. SH 130 would be retained, but only as a bypass route.

[TEG24601]

Building on top of a freeway, while exciting, and positive for those living near the freeway, is a very short-sighted way to solve issues with freeways.  What happens when there is an accident and the nearest emergency access is very far away, and you can't simply airlift people out?  What happens when traffic grows to the point that it is just one solid traffic jam?

That being said, it looks interesting.  Let us hope that they think ahead, and perhaps, create auxiliary lanes, that won't be used initially, so they can expand when traffic demands it.

[thisdj78]

If they are going to build a freeway tunnel, run it from I-35 to Mopac under Cesar Chavez.

There's two things Austin needs before expanding 35:

A real loop (improving 183 east somewhat solves that)
A cross town freeway (as mentioned above)

[AustinRoads]

If you look at an aerial of the 35N to 183N flyovers, they go right over the business properties (same with 1604/281 in San Antonio as well), so proximity to the frontage wouldn't be an issue.

Ignored again is the matter of vertical clearance.  The ramps at 1604/281 and the lone ascending flyover at 35/183 are quite steep due to the lack of right of way in both locations.  Trust me, if you've ever been stuck behind a truck negotiating the ramp at 183, they take it very slowly.  New steep flyovers for a truck bypass will cause more congestion.

Moving the trucks off of current 35 is one of the goals here.  The ramps at 290/35 are a much easier task for truckers, and traffic rarely backs up past there.

A cross town freeway (as mentioned above)

Downtown Austin is a little over 2 miles across, so I don't see how this solves anything.  Traffic is still going to end up on 35 and MoPac.  Congestion patterns in Austin are longitudinal, not latitudinal.

[thisdj78]

Downtown Austin is a little over 2 miles across, so I don't see how this solves anything.  Traffic is still going to end up on 35 and MoPac.  Congestion patterns in Austin are longitudinal, not latitudinal.

Size of downtown shouldnt really matter though, people dont want to encounter lights to cross a major city, so the only alternative (majority of the time) is to take 35 to as close as you can get to your destination.

Just look at Stockton, CA: way smaller city, less traffic but similar in that they have only a parallel set of freeways going through it (I-5 and SH99) yet they have a crosstown freeway connecting the two highways and likely for a reason. Traffic is longitudinal because it doesn't have a choice, but there are communities spreading out farther west. For example:

1) if someone from Cedar Park wants to get to Congress street just south of the river, they'll likely take 183 to 35 south to Riverside. With a connector freeway between Mopac and 35, that provides an alternative. Also, I'm sure there will be folks using it to go the opposite direction vs up 35 then 183.

In addition, adding overpasses on 360 between Lamar and 183 could provide similar relief.

So in summary, taking the money that could be used towards this tunnel and putting it towards upgrading 183, 360 and connecting 35 to Mopac through downtown would probably provide the same amount of traffic relief IMO.

[ethanhopkin14]

All I gots to say is good luck with that. It seems completely unfesible and might be completed 50 years after I die.

[thisdj78]

All I gots to say is good luck with that. It seems completely unfesible and might be completed 50 years after I die.

Pretty much. Why I say use the money elsewhere on other freeway projects.

[TXtoNJ]

It's all because the people in economically poor East Austin feel "separated" because there is a freeway between them and downtown.  That is not the cause of their problems, and putting a $60 billion parkway in there is not going to fix that.

Sort of. East Austin is gentrifying, and the new, rich (white) residents are wanting to beautify the area and connect it to downtown. That's primarily why I think this will actually get done.

[texaskdog]

On a slightly different note, do any of my Austin friends know if they are extending Far West Blvd to 2222?  It sure looks like it driving by there, unless they are just putting houses in and need the road for that.