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I-35 Other San Antonio Area Roads
Interstate 35/San Antonio-Austin Corridor

This page last updated January 25, 2013

I-35 Corridor map

The San Antonio-Austin Corridor is the busiest inter-metro Interstate in Texas with traffic counts exceeding 100,000 south of New Braunfels and north of San Marcos.  The corridor serves a booming region with an aggregate population of 3.7 million stretching 100 miles from South San Antonio to Georgetown north of Austin. The Corridor consists of Bexar, Guadalupe, Comal, Hays, Travis, and Williamson counties and the cities of San Antonio, Live Oak, Selma, Schertz, New Braunfels, San Marcos, Kyle, Buda, Austin, Round Rock, and Georgetown. This page addresses the 48 mile core of the corridor: the section between the San Antonio and Austin urban areas from FM 482 in Schertz to SH 45 in southern Travis County. To continue south, see the I-35 North page in the San Antonio Area Freeway section of this site.


Roadway configuration


  • 6 lanes from FM 482 to Solms Rd.
  • 8 lanes in New Braunfels from Solms Rd. to FM 306
  • 6 lanes from FM 306 to SH 45

There is a left-lane truck restriction in effect for the entire corridor from just inside Loop 1604 in Live Oak to north of Georgetown.


Nearly continuous access roads along entire route. Access roads now continue over the Guadalupe River in New Braunfels and the Blanco River in San Marcos and through and north of Kyle. One-way access roads from San Antonio to Kohlenberg Rd. north of New Braunfels; from Posey Rd. to Yarrington Rd. in San Marcos; and from Kyle Pkwy. into Austin.


I-35 has continuous illumination between Solms Rd. and FM 306 in New Braunfels and from Center Point Rd. to the Blanco River in San Marcos. Nighttime illumination is also provided at interchanges between FM 482 and Solms Rd. and at the interchange of SH 45 just north of Buda.


In 2008, TxDOT installed Intelligent Traffic System (ITS) equipment throughout the corridor consisting of cameras, speed detectors, and dynamic message signs. This system connects to the TransGuide ITS system in San Antonio and the CTECC ITS system in Austin, thus providing real-time corridor traffic information to motorists in both cities.


Interstate 35 is currently the only freeway tying the San Antonio/Austin region together and, as a consequence, is overloaded on many sections. Most, if not all, traffic counts have increased well over 100% since 1990. All counts in the corridor now exceed 70,000 vehicles per day, with over 100,000 VPD now reported from New Braunfels south and from San Marcos north.

In addition to local growth, NAFTA has put an additional strain on the corridor. As a result, officials lobbied to have it designated as a NAFTA Superhighway to secure federal funding for various conventional and ITS improvements and the entire corridor has been upgraded to a six and eight lane facility in the past 20 years.

Speed limits

  • 70 mph along entire corridor

Future plans

There are no future expansion or upgrade plans for the corridor for the foreseeable future.

SH 130

SH 130 tollway To help alleviate the growing traffic problems in the I-35 corridor, a parallel tollway, SH 130, was built. For more information, see the the SH 130 page.

Additional information

I-35 Trade Corridor Study

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This page and all its contents are Copyright 2019 by Brian Purcell

The information provided on this website is provided on an "as-is" basis without warranties of any kind either express or implied.  The author and his agents make no warranties or representations of any kind concerning any information contained in this website.  This website is provided only as general information.  The author expressly disclaims all liability with respect to actions taken or not taken based upon the information contained herein or with respect to any errors or omissions in such information.  All opinions expressed are strictly those of the author.  This site is not affiliated in any way with any official agency.