If there’s one thing guaranteed to spark spirited conversation in Texas, it’s construction along I-35. The highway stretches from Laredo to Minnesota, but it’s the Texas portion, especially the part that slices through Austin, that feels perpetually under construction. For anyone traveling through Central Texas, the downtown stretch is the true wildcard. With postcard-worthy views of the Capitol and the University of Texas Tower, it offers plenty to look at, but even minor roadwork can turn that view into an extended standstill.

Today, those delays reflect something bigger: a generational reinvestment in the region’s most critical transportation corridor. TxDOT and the City of Austin are reshaping the way people move through, around, and between neighborhoods that have historically been separated by the interstate.

“Austin is undergoing a major facelift, with five large-scale infrastructure improvements,” says Paco Guerrero, P.E., Vice President at Pape-Dawson. Two of those efforts – the expansions to the Austin-Bergstrom International Airport and the Walnut Creek Wastewater Treatment Plant – boost regional capacity but have little direct impact on I-35. The other three, however, sit at the heart of downtown and will redefine how the community interacts with the urban core.

Pape-Dawson is contributing engineering expertise across all three:

• I-35 Capital Express Central
  • A reimagining of the corridor that will lower portions of the freeway approximately 50 feet and add new east–west vehicle and pedestrian connections, removing long-standing barriers between neighborhoods.
• Austin Convention Center Redevelopment
  • A modernized, expanded convention center designed to better integrate with surrounding districts and support Austin’s vibrant visitor economy.
• Project Connect
  • A comprehensive transit program introducing new light rail and commuter rail options to support sustainable mobility.

These efforts represent years of planning, technical collaboration, and community engagement. Pape-Dawson Practice Leader Stacey Gould, P.E., notes that public feedback played a key role in shaping the direction of I-35. “They want it to feel like one city from one side to the other, and the depressed main lanes, Cap and Stitch connectivity, and vehicular bridges at grade across the highway will promote that feeling,” she says.

The Underground Work Powering the Above-Ground Vision

While the visible construction will catch the public’s eye, a large portion of the work is happening beneath Austin’s streets. “Our role is to find a place for all the water and wastewater utilities that crisscross I-35,” explains Guerrero.

Pape-Dawson recognized early that utility planning for these overlapping downtown projects, CapEx Central, the Convention Center, and Project Connect, needed a coordinated strategy. Guerrero describes the benefit clearly: “To shut down a large transmission main line only once, rather than three times, will save Austin a lot of headaches, time, and money.”

One of the most complex challenges came as engineers explored the impacts of lowering I-35. The shift exposes existing utilities and forces a rethinking of wastewater flows. “That was a problem for wastewater, which is a gravity system,” says Gould. “We needed to find new places to tie those lines to outside the I-35 corridor, inside the City of Austin right of way.”

This necessity led to a first-of-its-kind shift: In order for the utility relocations to work inside the TxDOT ROW, the relocation improvements had to extend beyond the TxDOT ROW, into City streets, in some instances for several blocks. This is also part of the project funded by TxDOT. “It’s a unique part of the project that came from our schematic design,” Gould adds.

Austin’s Model for Other Cities in Transition

Austin’s approach builds on lessons from cities like Dallas, whose Klyde Warren Park demonstrated how infrastructure can reconnect urban neighborhoods. Guerrero and Gould highlight several insights for cities planning major transformations:

Secure robust funding early on

Such efforts require sustained financial commitment. “That hasn’t been a problem here, since it’s been a TxDOT priority, but the money you spend in the design phase can multiply in savings later during construction,” mentions Guerrero.

Accept that major projects take time

“This stretch of I-35 hasn’t been touched since the 1950s,” Guerrero notes. Addressing long-standing needs takes time, and design phases often depend on one another. Gould says, “If the roadway design isn’t complete, then we can’t finish the drainage and utilities design. Any changes in roadway design will cascade to other designs, too.

Know what’s below the surface

“Luckily, Austin has a robust GIS system with lots of information, and TxDOT has done an excellent job of gathering Surface Utility Engineering (SUE), geotechnical, and survey data along the corridor,” says Guerrero. Accurate information upfront prevents surprises later.

The Road Ahead

In the near term, Austin drivers will face years of challenging traffic, lane shifts, detours, and the familiar sight of excavators lining the corridor. Yet each delay is part of a much larger story: a downtown reconnecting itself, infrastructure being modernized for future generations, and a city positioning itself for continued economic and population growth.

So, the next time you find yourself idling behind a line of orange barrels, consider the transformation underway—and the complex network of utilities beneath your tires (and sometimes blocks away) making it all possible.