Skip to main content


The Texas Department of Transportation (TxDOT) is expanding approximately 20 miles of I-35 from N. Walters Street to FM 1103 in Bexar, Comal, and Guadalupe Counties. The I-35 NEX Program – including Central, South, and North projects – involves the construction of two elevated structures in each direction. The elevated structures will be constructed between the existing I-35 mainlanes and frontage roads. The program also includes incidental construction necessary to transition the elevated lanes and connectors with the existing highways including revisions to ramps and frontage roads and accommodations for drainage, utilities, signs, and other highway improvements.

The majority of construction will occur on weeknights to avoid traffic disruptions.

Stay connected and informed by following us on Twitter and Facebook @i35nexcentral. You can also call 726-800-4809 or email us at i35nexcentral@txdot.gov

The I-35 NEX Program was broken multiple project phases – Central, South Phases 1, 2, and 3, and North. The Central Project begins at I-410 N and extends north to FM 3009, approximately 9.5 miles; the South Phase 1 Project goes from I-410 South to I-410 North, approximately 4.2 miles; the 3.3-mile South Phase 2 Project is from I-410 South to N. Walters Street; the South Phase 3 Project goes from the I-35/I-410 South Interchange to FM 78, approximately .8 mile; and the North Project consists of 6.4 miles along I-35 from FM 1103 to FM 3009.

"Traditional build" and "design-build" are two different methods of approaching construction on a large project such as I-35 NEX Central. With a traditional build, architects and engineers are employed to design the project. Once the design is complete, a construction company will use that design to construct the project. In comparison, a design-build project utilizes one company to both design and build the project, which has several benefits, including streamlined processes, reduced costs, and agility to adapt to design obstacles.

The Central Project is being completed through a partnership between TxDOT and Alamo NEX Construction; the South Phase 1 Project is being constructed through a partnership between TxDOT and Lone Star Constructors, NEX. The other I-35 NEX projects are not yet under construction. This program was identified by the Texas Clear Lanes Initiative.

An HOV lane is a special lane reserved for carpools, buses, motorcycles, or emergency response vehicles. These lanes enable vehicles to bypass the traffic in the adjacent, unrestricted mainlanes. HOV lanes reduce congestion, promote mass transit services, improve road safety, and establish corridor reliability.

For more information or background on the entire I-35 NEX project please visit TxDOT projects and studies

To learn more visit the TxDOT San Antonio District