MoPac South — What the $825M Expansion Means for Zilker Austin TX Real Estate

The $825M MoPac South toll lane expansion is in active environmental review through May 3, 2026. Construction would temporarily use parts of Zilker Park. Here is what buyers and sellers need to know right now.

Tammy Davison
REALTOR®  ·  Published 2026-07-27  ·  Updated 2026-07-27

How does the MoPac South expansion project affect Zilker Austin TX real estate?

The MoPac South project — an $825M proposal to add two express toll lanes in each direction along 8.77 miles of MoPac from Cesar Chavez to Slaughter Lane — published its draft environmental assessment in February 2026 with a public comment period through May 3, 2026. The project’s footprint includes temporary construction use of parts of Zilker Park, impacts to the Ann and Roy Butler Hike-and-Bike Trail, the MoPac pedestrian bridge, and the Barton Creek Greenbelt. For buyers evaluating Zilker properties adjacent to MoPac, the project introduces meaningful uncertainty that is already being priced into offers. For sellers adjacent to MoPac, understanding the project’s scope and status is essential due diligence before listing.

The recommended Alternative 2C plan proposes two express toll lanes with elevated ramps near Barton Skyway — the interchange that sits at the western edge of Zilker Park where Barton Springs Road meets MoPac. Construction under this plan would temporarily use sections of Zilker Park, impact the Ann and Roy Butler Hike-and-Bike Trail, require construction barges on Lady Bird Lake during bridge widening, and temporarily close portions of the MoPac pedestrian bridge. The Barton Creek Greenbelt and Violet Crown Trail would also be temporarily affected. For a neighborhood whose value is fundamentally tied to these amenities, the construction period is a material consideration.

The draft environmental assessment is in its public comment period through May 3, 2026. The CTRMA held an in-person public hearing March 24 at Bowie High School and a virtual hearing beginning March 9. Opposition from Save Our Springs, Austin City Council Member Paige Ellis, and a coalition of Zilker and South Austin residents has argued the project warrants a full environmental impact statement rather than the current environmental assessment. Once the comment period closes, CTRMA will review feedback and submit a final assessment to TxDOT. Construction is not imminent — the project remains in environmental review, not construction authorization.

For buyers: eastern Zilker properties adjacent to MoPac are being evaluated with the expansion uncertainty as a background factor. This is most visible in hesitation on properties directly on or near the MoPac right-of-way. For sellers in these sections: transparency about the project’s status, the comment period, and the construction timeline is better positioning than ignoring it — buyers will find it regardless. For buyers and sellers in interior and western Zilker: the direct impact is more limited, though park access disruption during construction would affect the whole neighborhood. The project is a long-term infrastructure improvement with a near-term construction disruption cost that both parties should price into their analysis.

MoPac South is the most significant infrastructure decision affecting Zilker real estate in a generation. The project is not yet approved, but the draft environmental assessment’s detail about construction impacts on Zilker Park, Lady Bird Lake, and the Greenbelt has introduced meaningful uncertainty for buyers evaluating eastern Zilker properties. Both buyers and sellers who understand where the project stands — in environmental review, not construction — are making better decisions than those treating it as either imminent or irrelevant.

Tammy DavisonREALTOR®  ·  Realty Austin | Compass RE Texas

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