Interstate 35 in Texas is a massive, evolving artery that shapes urban life daily

Countries & Cities · Published 15 October 2026 Swipe more like this →

In short: Spanning over 500 miles, Interstate 35 is the backbone of Texas transit. From its origins as a post-war inter-regional highway to its current multi-billion dollar expansion projects, the road serves as both a vital NAFTA trade corridor and a controversial social barrier that continues to redefine the state's urban landscape.

Interstate 35 stretches from Laredo to the Red River, covering more of its total length in Texas than in any other state. The highway is not a single continuous path; north of Hillsboro, it splits into I-35E through Dallas and I-35W through Fort Worth, which later rejoin in Denton. This complex route has required constant adaptation, including the addition of elevated express lanes in Austin during 1975 to navigate tight spaces between the University of Texas and local cemeteries. The highway's history is marked by unusual discoveries, such as the 1963 finding of Inner Space Cavern, which was located 33 feet below grade during overpass construction.

The corridor is currently undergoing massive transformations, most notably the Capital Express project in Austin. This $4.9 billion initiative aims to rebuild the highway through downtown, potentially burying sections below-grade and adding managed lanes. However, the project has faced significant public pushback. Critics argue that the expansion will displace residents, increase carbon emissions, and worsen congestion through induced demand. In 2022, a lawsuit filed by organizations like Rethink35 alleged that the Texas Department of Transportation was segmenting the project to bypass rigorous environmental reviews, though the case was later dismissed.

Beyond Austin, the highway remains a critical economic engine. As a primary NAFTA corridor, it carries heavy freight, leading to truck restrictions in the far left lanes of the San Antonio and Austin areas to manage traffic flow. Projects like the Main Street Texas expansion have sought to modernize the route through McLennan and Bell counties, replacing bridges and widening lanes. Despite these efforts, the stretch between San Antonio and Austin remains one of the most congested in the entire Interstate System, prompting ongoing debates about whether to continue expanding the highway or to explore alternatives like commuter rail and bypass loops.

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