It’s time for I-35 to be 8 lanes from DFW to San Antonio

[thisdj78]

Seems like just yesterday they finally finished 6-laning I-35. I've driven the entire length in various segments over the last month, and it feels like 20 years ago (when most of it was still just 4 lanes), with the worst choke points being between San Antonio/Austin and Belton/Temple.

[MaxConcrete]

I have driven from DFW to Austin a few times in recent years, and my observation is similar. Referring mainly to the section between Hillsboro and Austin: traffic is heavy. It still moves at the posted speed limit (or faster) most of the time, but additional traffic growth may cause slowdowns and delays.

The section between Hillsboro and Georgetown (SH 130) should have been built to 4x4. The existing 3x3 is designed for easy widening in most places, but it will still be expensive and disruptive to get the widening done.

I'm not aware of any plans for continuous 4x4 between Austin and Georgetown. There is planning for 4-3-3-4 on the I-14 multiplex section between Belton and Temple. But that won't happen anytime soon.

[ElishaGOtis]

Between Austin and San Antonio I could see a case for, especially with AADT reaching over 120k in some places. Between Austin and Belton there could be a case despite the slightly lower AADT, same thing between Belton/Temple and Waco. However, I think capacity could be significantly increased with simple traffic operations improvements on the frontage roads in rural areas, such as replacing the all-way stops with signals or (shudders to think about this) roundabouts... Not many realize that the frontage roads technically add about 4-8 lanes of capacity depending on the location, and in rural areas, they're technically just another classic divided highway with slightly better access control (RCUTs are effectively required for any side-street access to the corridor).

Before anyone says this should be fictional, I'm certain that TxDOT has real plans in mind for doing exactly what OP suggested in the future. As such, what are the current programmed improvements to the corridor as we speak?

[MaxConcrete]

Before anyone says this should be fictional, I'm certain that TxDOT has real plans in mind for doing exactly what OP suggested in the future. As such, what are the current programmed improvements to the corridor as we speak?

See the 2025 UTP.

There's very little in the planning phase outside of the downtown Austin mega-project and the $700 million Belton-to-Temple section. (Project 9 in the Waco district map is already underway.)

I don't know the current total cost of I-35 in Austin, but I'm thinking it's around $5 billion. This project is the massive money consumer on I-35 for the next 10 years, so not much else will get done.

[Ellie]

Everything between Georgetown and San Antonio needs it, but the bit between Dallas and Georgetown does not. From Waco to Belton is arguable, but the other bits are pretty rural and really don't have heavy enough traffic to merit it.

Amusingly, I-35W is 2x2 north of Hillsboro. That surprised me the first time I took it.

[thisdj78]

Everything between Georgetown and San Antonio needs it, but the bit between Dallas and Georgetown does not. From Waco to Belton is arguable, but the other bits are pretty rural and really don't have heavy enough traffic to merit it.

Amusingly, I-35W is 2x2 north of Hillsboro. That surprised me the first time I took it.

Between Belton and Temple definitely needs it, but sounds like that is in the plans as the I-14 project moves east from Belton.

And yes I-35W needs to be 3x3.

I wonder if there is a need for an HOV or managed lanes. An argument could be made for one from San Antonio to Temple. It would be a record breaker (current longest HOV lane is in Utah at 80+ miles)

[Anthony_JK]

Between Austin and San Antonio I could see a case for, especially with AADT reaching over 120k in some places. Between Austin and Belton there could be a case despite the slightly lower AADT, same thing between Belton/Temple and Waco. However, I think capacity could be significantly increased with simple traffic operations improvements on the frontage roads in rural areas, such as replacing the all-way stops with signals or (shudders to think about this) roundabouts... Not many realize that the frontage roads technically add about 4-8 lanes of capacity depending on the location, and in rural areas, they're technically just another classic divided highway with slightly better access control (RCUTs are effectively required for any side-street access to the corridor).

Before anyone says this should be fictional, I'm certain that TxDOT has real plans in mind for doing exactly what OP suggested in the future. As such, what are the current programmed improvements to the corridor as we speak?

Am I assuming wrong that the frontage roads there are one-way and continuous?? Not sure roundabouts would be appropriate. Grade separated overpasses with connecting roadways between the frontage roads and crossing roads would suffice, I'd think.

[Bobby5280]

I think I-35 from Waco down to San Antonio definitely needs to be a minimum of 4x4 lanes or greater. The section North of Waco to Hillsboro could get by with a 3x3 configuration for the time being. In another 10-15 years further upgrades might be necessary if Texas keeps sucking population from other states. Most of the growth in the DFW region is spreading on the North side toward the Red River. But there are places South of the metro that are growing too.

And yes I-35W needs to be 3x3.

The 2x2 segment between the South I-35 Y and Burleson is pretty old. Just about all the bridges going over I-35W are pretty old in design. Most are narrow and have no shoulders. The upside is the bridge pillars are spaced far enough apart that an interior left lane could be added on I-35W if TX DOT wanted to do an upgrade on the cheap. A complete 3x3 re-build like what they did with I-35 farther South would obviously cost a lot more money.

[Road Hog]

That's where I think TxDOT is leaning hard on NTTA to finish a 360 Tollway southern extension. Chicken and egg.

[thisdj78]

Between Austin and San Antonio I could see a case for, especially with AADT reaching over 120k in some places. Between Austin and Belton there could be a case despite the slightly lower AADT, same thing between Belton/Temple and Waco. However, I think capacity could be significantly increased with simple traffic operations improvements on the frontage roads in rural areas, such as replacing the all-way stops with signals or (shudders to think about this) roundabouts... Not many realize that the frontage roads technically add about 4-8 lanes of capacity depending on the location, and in rural areas, they're technically just another classic divided highway with slightly better access control (RCUTs are effectively required for any side-street access to the corridor).

Before anyone says this should be fictional, I'm certain that TxDOT has real plans in mind for doing exactly what OP suggested in the future. As such, what are the current programmed improvements to the corridor as we speak?

Am I assuming wrong that the frontage roads there are one-way and continuous?? Not sure roundabouts would be appropriate. Grade separated overpasses with connecting roadways between the frontage roads and crossing roads would suffice, I'd think.

They are one way now, but you can make roundabouts with one way frontage roads. I've seen them in Europe, it's usually either one big roundabout that the freeway passes over or under or two smaller roundabouts on each side of the freeway:

https://maps.app.goo.gl/Zo33eUjNeyTprENx9?g_st=com.google.maps.preview.copy

[Anthony_JK]

Between Austin and San Antonio I could see a case for, especially with AADT reaching over 120k in some places. Between Austin and Belton there could be a case despite the slightly lower AADT, same thing between Belton/Temple and Waco. However, I think capacity could be significantly increased with simple traffic operations improvements on the frontage roads in rural areas, such as replacing the all-way stops with signals or (shudders to think about this) roundabouts... Not many realize that the frontage roads technically add about 4-8 lanes of capacity depending on the location, and in rural areas, they're technically just another classic divided highway with slightly better access control (RCUTs are effectively required for any side-street access to the corridor).

Before anyone says this should be fictional, I'm certain that TxDOT has real plans in mind for doing exactly what OP suggested in the future. As such, what are the current programmed improvements to the corridor as we speak?

Am I assuming wrong that the frontage roads there are one-way and continuous?? Not sure roundabouts would be appropriate. Grade separated overpasses with connecting roadways between the frontage roads and crossing roads would suffice, I'd think.

They are one way now, but you can make roundabouts with one way frontage roads. I've seen them in Europe, it's usually either one big roundabout that the freeway passes over or under or two smaller roundabouts on each side of the freeway:

https://maps.app.goo.gl/Zo33eUjNeyTprENx9?g_st=com.google.maps.preview.copy

That example, though, is a more conventional "dogbone" or "teardrop" double roundabout interchange, with conventional ramps connecting to the mainlanes, rather than to continuous frontage/access roads.


moto g power (2022)

[longhorn]

The section between Belton and Temple needs to be expedited. It's a bottleneck. Smooth out the elevation transition, leaving Belton south; it's why trucks slow down to crawl to go up the hill.

[bwana39]

My take is different. I am not a proponent of long-haul 4x4 freeways.

Build up US-281 (I-37) from San Antonio to Hico  (US-67 more or less) perhaps even  to meet I-44 in Wichita Falls. It lets traffic miss at least Austin and Waco and much of DFW. It would cause less congestion during construction and allow the western reached of central Texas to be built up.

[Bobby5280]

I think US-281 going North out of San Antonio needs to be upgraded to Interstate standards at least as far North as Lampasas regardless of what future improvements are made to I-35.

[webny99]

I think US-281 going North out of San Antonio needs to be upgraded to Interstate standards at least as far North as Lampasas regardless of what future improvements are made to I-35.

I agree, in the long term a mega-bypass of Austin allowing traffic to drop in to San Antonio from the north via I-14 and US 281 would be awesome. But for now, at least continuing the freeway north to Bulverde and eventually north to Johnson City would be a good start.

[motorola870]

I think I-35 from Waco down to San Antonio definitely needs to be a minimum of 4x4 lanes or greater. The section North of Waco to Hillsboro could get by with a 3x3 configuration for the time being. In another 10-15 years further upgrades might be necessary if Texas keeps sucking population from other states. Most of the growth in the DFW region is spreading on the North side toward the Red River. But there are places South of the metro that are growing too.

And yes I-35W needs to be 3x3.

The 2x2 segment between the South I-35 Y and Burleson is pretty old. Just about all the bridges going over I-35W are pretty old in design. Most are narrow and have no shoulders. The upside is the bridge pillars are spaced far enough apart that an interior left lane could be added on I-35W if TX DOT wanted to do an upgrade on the cheap. A complete 3x3 re-build like what they did with I-35 farther South would obviously cost a lot more money.

I honestly would do what they did for I35E over the years from US77 at the southside of Waxahachie to Hillsboro.

They are in the planning stages for 3x3 from 174 to Alvarado on I35W. Hopefully this would mean an increased height at 174 for the northbound underpass that merges on to I35W height is less than 15ft.

[Anthony_JK]

My take is different. I am not a proponent of long-haul 4x4 freeways.

Build up US-281 (I-37) from San Antonio to Hico  (US-67 more or less) perhaps even  to meet I-44 in Wichita Falls. It lets traffic miss at least Austin and Waco and much of DFW. It would cause less congestion during construction and allow the western reached of central Texas to be built up.

If US 281 could be freewayized up to Wichita Falls, that, combined with Bobby's idea of an I-32/US 287 freeway through Wichita Falls and the proposed I-27 and I-14 corridors, could open that city up to some major development. I'd still prefer it to be signed as I-33 north of San Antonio, just to respect the grid.

(I'll stop here since it's getting a bit too Fictional now.)


moto g power (2022)

[Anthony_JK]

Between Austin and San Antonio I could see a case for, especially with AADT reaching over 120k in some places. Between Austin and Belton there could be a case despite the slightly lower AADT, same thing between Belton/Temple and Waco. However, I think capacity could be significantly increased with simple traffic operations improvements on the frontage roads in rural areas, such as replacing the all-way stops with signals or (shudders to think about this) roundabouts... Not many realize that the frontage roads technically add about 4-8 lanes of capacity depending on the location, and in rural areas, they're technically just another classic divided highway with slightly better access control (RCUTs are effectively required for any side-street access to the corridor).

Before anyone says this should be fictional, I'm certain that TxDOT has real plans in mind for doing exactly what OP suggested in the future. As such, what are the current programmed improvements to the corridor as we speak?

Am I assuming wrong that the frontage roads there are one-way and continuous?? Not sure roundabouts would be appropriate. Grade separated overpasses with connecting roadways between the frontage roads and crossing roads would suffice, I'd think.

They are one way now, but you can make roundabouts with one way frontage roads. I've seen them in Europe, it's usually either one big roundabout that the freeway passes over or under or two smaller roundabouts on each side of the freeway:

https://maps.app.goo.gl/Zo33eUjNeyTprENx9?g_st=com.google.maps.preview.copy

That example, though, is a more conventional "dogbone" or "teardrop" double roundabout interchange, with conventional ramps connecting to the mainlanes, rather than to continuous frontage/access roads.

I'm talking more about integrating roundabouts with continuous one-way access roads. I'd think that would not be the most effective or convenient means, unless you had bypass roads allowing the frontage road traffic to pass over the roundabout movements.



moto g power (2022)

moto g power (2022)