Welcome to the

183A Phase III Project

The Central Texas Regional Mobility Authority and the Texas Department of Transportation studied the proposed extension of 183A Toll. The Environmental Assessment (EA); a comprehensive full disclosure document comprised of the environmental studies performed, thoroughly analyzed the 6.6-mile tollway project. 

The study led to the approval of a plan to extend 183A north from Hero Way to north of SH 29 as Phase III of the 183A system. The 6.6-mile proposed tollway project will have two tolled lanes in each direction to start, and will ultimately be widened to three lanes in the future. The proposed tollway is planned to be located mostly in the existing right-of-way within the median of the US 183 corridor. The extension will also feature a shared use path north from Hero Way to the proposed Seward Junction Loop project.
The project is currently undergoing final design and construction is anticipated to begin in early 2021.


Williamson County, most notably in Cedar Park, Leander, and Liberty Hill, is experiencing a population boom. Between 2016 and 2040 Cedar Park’s population is projected to grow by 31 percent, Liberty Hill by approximately 44 percent, and Leander will see a drastic 271 percent. The corridor is expected to continue to attract residential and commercial development, further intensifying congestion and delays.

With this unprecedented growth, traffic volumes along US 183 are expected to increase by nearly 200 percent over the next 25 years driving the need for proactive congestion relief. Increased congestion along the existing facility lanes can lead to accidents occurring at a higher frequency and severity level at intersection locations. The projections for sustained growth proves the need for action now.

Extend the existing 183A from Hero Way to SH 29, adding up to three tolled lanes in each direction along the 6.6-mile stretch. 
This solution will: 

  • Provide a reliable, predictable and time-saving option for drivers and emergency vehicles. 
  • Accommodate community growth and development along and to the north of the corridor. 
  • Provide an alternative route free of signalized intersections along the corridor. 
  • Minimize community impacts by working mostly within existing right-of-way. 

Existing bicycle and pedestrian accommodations along 183A and US 183 within the project limits are currently limited to crosswalks and ramps at Hero Way, Bryson Ridge Trail, and SH 29, and paved outside shoulders along the general-purpose lanes. 

The proposed 183A Phase III project would provide a 10-foot-wide, paved bicycle and pedestrian shared-use path from Hero Way to the planned Seward Junction South. A connecting shared use path would be included to provide trail access to the City of Leander’s planned South San Gabriel River park. 183A Phase III Build Alternative will provide a net benefit to bicyclists and pedestrians. 

Our environmental team studied the potential impacts of the 183A Toll Road Phase III to the human and natural environment. The study was completed in August 2019 and the Texas Department of Transportation (TxDOT) has issued a Finding of No Significant Impact (FONSI) for the proposed project.

The Environmental Assessment is available online on this website - 183A.com/EA. It can also be inspected in-person Monday through Friday between the hours of 8 a.m. and 5 p.m. at the Central Texas Regional Mobility Authority at 3300 N. I-35 Frontage Road, Suite 300, Austin, TX 78705 or at the TxDOT Austin District Office at 7901 N Interstate Hwy 35, Austin, TX 78753.


Anticipated construction start date is early 2021.

The project is currently anticipated to be completed in 2024.

One Build Alternative was proposed and evaluated for the facility. It meets the purpose of and need for the project by providing additional highway capacity in the form of three tolled, grade-separated main lanes in each direction. The added capacity would relieve forecast traffic on the existing US 183 facility, which would continue to serve as a non-tolled travel alternative to the 183A tolled lanes. Consequently, the Build Alternative will accommodate forecast traffic volumes and alleviate associated traffic congestion and was selected as the Preferred Alternative for further devleopment and construction. 

A No-Build Alternative assumes that the tollway would not be built. Although the No-Build Alternative does not meet the Purpose and Need of the project, it served as a baseline for comparison with the Build Alternative. During the Environmental Assessment, the Build Alternative would have had to have significant environmental impacts to outweigh the No-Build Alternative’s inability to meet the Purpose and Need before the No-Build Alternative could have been selected as the Preferred Alternative. 

Most of the proposed Build Alternative will be constructed within the existing right-of-way (ROW) of 183A and US 183. We anticipate that approximately 19.3 acres of additional ROW may be required near the northern portion of the proposed project to provide sufficient area for constructing the transition of US 183 for approximately 1.1 miles north of SH 29.

The proposed 183A facility would stay within the existing 183A and US 183 alignment and no new-location roadways are proposed as part of the project. No displacements and relocations are anticipated and physical access to residences and community resources would remain. Changes to neighborhood cohesion, existing access to specific services, or recreation patterns at public facilities are not expected to occur under the project.

Project construction would occur within the existing 183A and US 183 ROW and easements and the proposed 19.3 acres of additional ROW north of SH 29.

No detours or road closures are anticipated since the existing US 183 lanes would remain open. Temporary lane closures would be minimal and primarily associated with construction of entrance/exit ramps and grade separated intersections. Consequently, economic impacts to local businesses associated with roadway access during construction are not anticipated. The expenditures of contractors and employees during the project’s construction phase would be expected to benefit the local economy.

The Environmental Assessment evaluated noise impacts of the proposed project to determine if noise barriers are needed/required. The noise barrier analysis determined that traffic noise impacts would occur at 24 homes, the planned South San Gabriel River park, and the New Life Church playground. The projected increase in noise levels is due to the increase in roadway traffic lanes and traffic volumes. Noise levels already approach or exceed noise abatement criteria at seven locations under existing conditions. Without the proposed project, traffic noise would increase over existing conditions because of increased traffic volumes.

Because of the anticipated noise level increase associated with the proposed project, a noise analysis was conducted. The results of that analysis indicated that one combination of two noise barriers would be feasible and reasonable as a noise abatement measure adjacent to the future South San Gabriel River Park planned by the City of Leander. Other noise walls, where feasible, would not be reasonable for the impacted receivers since they would exceed TxDOT’s cost-effectiveness criteria. No other noise barriers qualified for incorporation into the proposed project.

The Environmental Assessment reviewed the potential impacts of the project to the natural environment along the corridor. Given the project is occurring mostly within existing ROW, the study found no significant impacts. Complete analysis and findings are available as a part of the Environmental Assessment.

The final plan of funding the project has not been completed; however, it is expected that funding for the project will be through a combination of revenue bonds and a federal Transportation Infrastructure Finance and Innovation Act (TIFIA) loan. Revenues from tolls paid by users will be used to pay principal and interest payments on the bond and TIFIA loan and pay for the long-term maintenance of the facility.

This project will cost approx. $260 million, which includes total project costs, but excludes financing cost.

Information about the project can be obtained online at www.183a.com or by contacting the project team via email at 183aphase3@ctrma.org or by phone at 512-996-9778. 

The project team is also available to meet with neighborhood associations, community groups and others to discuss issues of concern, various improvement options and the results of technical and environmental analyses.