Work Set to Begin on Expanding I-35, One of Texas’ Most Congested Roads

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Updated May 27, 2022
preliminary Rendering I-35 NEX Central project Texas
A preliminary rendering of the future I-35 NEX Central project.
Texas Department of Transportation

Ground has been broken for a $1.5 billion project to expand part of Interstate 35 in the San Antonio, Texas, area, with elevated lanes running above current lanes.

Preliminary work has begun by the design-build contractor on the project, Alamo NEX Construction, which is a partnership of Ferrovial Construction and Webber LLC.

map I-35 NEX Central section of I-35 expansion San AntonioMap of the 9.5-mile central section of the I-35 Northeast expansion project.Texas Department of TransportationCalled the I-35 Northeast Expansion Central project, it will expand 9.5 miles between I-410 North in Bexas County and FM 3009 in Guadalupe County. The project involves building two sets of elevated, non-tolled lanes consisting of a high-occupancy vehicle lane and two general lanes in each direction. Flyovers will be constructed at I-410 North and Loop 1604 West.

The elevated lanes are essentially two long bridges that will eventually stretch 15 miles when adding in south and north sections to be built after the central section is completed. The lanes will add to the current four lanes in each direction of I-35.

The entire project, including south and north sections, is estimated to cost $6 billion and expand 20 miles of I-35 from North Walters Street to FM 1103 in Bexas, Comal and Guadalupe counties.

The Texas Department of Transportation says the central section is already overcapacity. It has been named one of Texas’ most congested roadways by the Texas A&M Transportation Institute. An estimated 200,000 drivers travel the road each day, with that number expected to double by 2044.

The I-35 section is also part of a major trade route between Mexico and Canada. 

The goal of the NEX Central project is to increase mobility, reduce congestion and improve driver safety.

Preliminary geotechnical drilling and utility potholing have begun on the NEX Central project, according to Ferrovial. Construction is set to begin in summer and be completed by 2027.

The TxDOT video below gives a preliminary idea of what the completed central project would look like: