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  • Writer's pictureRachel Timokhina, CP&Y Blog Writer

One Year Later: SH 45SW Toll Road

Updated: Sep 14, 2020

Celebrating its one-year anniversary this June, the SH 45SW Toll Road's history began over 23 years ago. Initially approved in 1997, the 45SW project that we celebrate today began in earnest in 2013.

Not everyone was convinced.

Because this project was to pass over the Barton Springs Segment (BSS) of the Edwards Aquifer, the potential environmental impacts to this area were top of mind. The Edwards Aquifer feeds into Austin’s iconic Barton Springs, which is designated by the Environmental Protection Agency (EPA) as a sole source of drinking water for 1.7 million people. This is also a valuable water source used for industry and agriculture needs. Additionally, this area is home to the federally protected Barton Springs salamander. Residents also worried that this new avenue would actually increase non-local traffic through neighborhoods adjacent to the project.

The proposed toll road offered solutions.

The Central Texas Regional Mobility Authority and its partners listened to the community and developed what would become known as an industry-leading “greenfield” project. The 45SW project utilized the following methods to mitigate or avoid environmental impacts:

  • Native plants were used throughout to enhance wildlife habitat and roadway aesthetics.

  • The road is surfaced with a Permeable Friction Course (PFC), a specialized type of porous type of pavement that absorbs contaminants to reduce water pollution. This pavement also increases driver safety by providing better grip for vehicles.

  • Designers made sure that the roadway alignment avoided the Aquifer’s recharge features.

  • Water quality ponds are spaced along the toll road to collect stormwater and remove contaminants from runoff before releasing the water into the environment.

Traffic modeling showed residents that 45SW would significantly relieve neighborhood congestion. In fact, estimates predicted that 45SW would save drivers 9 to 17 minutes commuting time to Central Austin. That’s an 18% reduction that would save drivers $12.4 million per year.

The project’s Environmental Impact Statement and Record of Decision were signed in only 20 months. Construction began in November 2016 and was completed ahead of schedule in June 2019. Going above and beyond, the 45SW project team met and exceeded the client and community’s expectations.

Now, multimodal facilities along the toll road include access to the future Violet Crown Trail with parking and a 4.5-mile-long, tree-lined biking and walking trail. There’s also a nature-viewing area at the Hill Country Classroom, a shaded kiosk with interpretive signage.

Trail signs are interactive when viewed with Trail Explorer by CTRMA, a free app that provides audio narration and augmented reality. On their website, the Mobility Authority even offers a downloadable coloring and activity book inspired by the surrounding nature of the trail.

For the 45SW Toll Road, Central Texas Regional Mobility Authority and the project’s teaming partners have received the following awards:

  • International Partnering Institute: Collaborative Project of the Year Award, 2020

  • American Public Works Association: Technical Innovation Award, 2020

  • Special District Program Awards: Technology Innovation: Operations Award, 2019

  • National Asphalt Pavement Association: Quality in Construction Award, 2019

  • American Council of Engineering Companies (ACEC), Texas Chapter: Gold in the Environmental category, and Silver in the Water Resources category, 2019

  • Greater Austin Business Awards Brookfield Residential Environmental Champion Award Sustainability and Innovation, 2018

Click here for more information about the environmental aspects of this project or click here to read specifics about the 45SW Toll Road as a transportation project. Find an aerial video of this project site here on YouTube. Reach out to the Central Texas Regional Mobility Authority to learn more at



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