About the MoPac South Environmental Study

The Environmental Study being conducted on this project is an Environmental Assessment (EA). An EA is a public document that includes an analysis of a full range of alternatives (including a “no build” alternative) and an assessment of potential environmental impacts through the National Environmental Policy Act (NEPA) process. An EA is prepared for projects for which the significance of the environmental impact is not clearly established, and, if a build alternative is approved, results in a “Finding of No Significant Impact” (FONSI). Public involvement is a crucial element of the EA process.


What are we trying to do?

  • Provide an opportunity for reliable travel times
  • Improve operational efficiency
  • Create a dependable and consistent route for transit
  • Facilitate reliable emergency response

What problems are we trying to address?

  • Current congestion levels are creating unreliable travel times
  • Forecasted population, traffic, and employment growth, resulting in increased congestion and delay
  • Emergency response times are impacted by traffic congestion


The preliminary alternatives proposed for the Study were:

  • Add General Purpose Lane(s) in each direction
  • Add High Occupancy Vehicle (HOV) Lane(s) in each direction
  • Add Transit Only Lane(s) in each direction
  • Add Express Lane(s) in each direction
  • Transportation Systems Management (TSM)/ Transportation Demand Management (TDM)
    • TSM: a collection of low-cost (non-capital intensive) strategies to enhance safety, reduce congestion and improve traffic flow
    • TDM: managing or decreasing the demand for auto-related travel by using a variety of measures to increase the operating efficiency of transportation facilities
  • No-Build, or “do nothing” alternative


Based on initial evaluation, the Express Lanes Alternative, along with the High Occupancy Vehicle (HOV) Lanes Alternative and the Transit Only Lanes Alternative were carried forward for further evaluation because each met the Purpose and Need for the project.

Each of the three remaining alternatives were evaluated further using the project Goals and Objectives and other criteria. In comparison to the other build alternatives and the No Build (Do Nothing) alternative, the Express Lanes Alternative was selected as the Recommended Build Alternative because it:

  • Offers reliable travel times for single occupancy vehicles, vanpools, busses and emergency vehicles
  • Provides the shortest peak period travel time for all vehicles, including those using the general purpose lanes
  • Provides over 3 million hours of annual travel time savings for all users compared to the No Build Alternative. That’s about 1.7 times more savings than HOV Lanes and 13 times more savings than Transit Only Lanes
  • Avoids unnecessary impacts to the natural and human environment and avoids and minimizes impacts to water quality
  • Delivers relief in a timely manner
  • Increases opportunities for transit and ridesharing and includes new bicycle and pedestrian facilities

Check out the MoPac South Environmental Study Open House #3 (February 26, 2015) Display Boards to learn more about the alternatives evaluation process and the recommendation of the Express Lanes Alternative.


After the initial roll-out of the Express Lane(s) Alternative, the project team developed six different potential operational configurations for the Alternative for consideration by the project team, transportation partners, and the community. 


The project team is working to identify the best configuration option for the Express Lane(s) Alternative; the decision will be shared with the public as soon as the information is available.

“The environmental review, consultation, and other actions required by applicable Federal environmental laws for this project are being, or have been, carried-out by TxDOT pursuant to 23 U.S.C. 327 and a Memorandum of Understanding dated December 16, 2014, and executed by FHWA and TxDOT.”
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3300 N. IH-35 Suite 300
Austin, TX 78705

(512) 996-9778 Email Us
Contact Us

3300 N. IH-35 Suite 300
Austin, TX 78705

Call (512) 996-9778
Email Us