City staff warns of higher costs, earlier commitment deadline as TxDOT splits I‑35 Capital Express project

City staff told the Austin Mobility Committee on Dec. 2 that the Texas Department of Transportation has split the Capital Express Central project into two bid packages, changing the schedule and tightening the city's decision timeline for so‑called cap and stitch (deck) elements.

Transportation Director Richard Mendoza and Transportation Officer Michelle Marks said TxDOT now plans an "advanced construction package" expected to go to bid in late 2026 and break ground in 2027 and an "ultimate construction package" — which would include the bulk of roadway widening and the horizontal cap decks — that TxDOT anticipates letting in 2029. Marks said that, despite the later construction dates, TxDOT has asked the city for an earlier financing commitment: "They're asking that much lead time because they wanna know what their designers need to design for inclusion in the bid package," she said.

The change shifts a previously anticipated 2026–2027 timeline and puts the city in a position where staff said it may need to make design and funding decisions at 30% design rather than at a more refined 60% level. The city's financial services representative warned that the risk profile has increased because the city's previously approved $104,000,000 commitment for roadway support elements was based on 30% design and a set contingency. Financial staff said a draft Advanced Funding Agreement (AFA) from TxDOT currently states the city would be responsible for any cost overruns and would not have a role in design or delivery for TxDOT's elements.

"The city must pay for all cost overruns," the city's financial speaker told the committee, adding that staff had expected 60% design to better calibrate costs before executing a final agreement. Marks explained the practical implication: change‑order work or including cap decks later in the project would likely require redesign and incur additional fees. Staff also noted that TxDOT continues to request a May 2026 decision if the city wants cap decks included in the original bid package; city staff said that inclusion can still occur later as a change order but with different cost‑and‑design outcomes.

Staff described next steps: additional design progress toward 60% in 2027, continuing negotiations with TxDOT, and a March work session for council that will outline potential funding and financing strategies for cap decks and on‑top amenities. Marks emphasized that staff will provide one‑on‑one briefings for council members ahead of the work session and that inclusion via change order remains an option through later project phases.

Park impacts and mitigation were presented alongside the project timeline. Ricardo Solis of Austin Parks and Recreation said TxDOT's mitigation package includes a proposed boardwalk identified under Section 4(f) of the U.S. Department of Transportation Act of 1966 and estimated at about $25,000,000. Solis said the Trail Conservancy would manage that project and that TxDOT had acquired certain fee‑simple parcels to stage construction barges; staff noted federal constraints on temporary closures of 6(f) lands and the need for careful coordination on mitigation timing and allocation.

What happens next: staff will provide a staff recommendation on northern‑stitch locations later in December (based on alternatives presented and public feedback) and a March work session with more detailed funding and financing options. Council action on any funding commitment for cap decks — should the council decide to include them in TxDOT's original bid package — would be requested by May 2026 per TxDOT's current schedule. The committee was warned that cost estimates at 30% design can vary widely and that the city's exposure to overrun risk remains an outstanding issue.