AUSTIN (KXAN) — The Texas Department of Transportation confirmed Tuesday the City of Austin has until fall 2024 to identify $350 million in funding sources to build its Our Future 35 Cap and Stitch program.

The program is a planned city-led project to be built concurrently with TxDOT’s I-35 expansion near downtown. TxDOT’s $4.5 billion in funding for its downtown project doesn’t cover the costs of building the caps — or deck plazas that can host community spaces — above the highway.

Instead, the city is leading the funding charge on the program. On Tuesday, a TxDOT spokesperson told KXAN $350 million is needed to build the infrastructure to support the deck, as well as fire life safety components.

“The upfront cost for the city would be approximately $350 million by fall 2024 for TxDOT to include deck plaza infrastructure in the plans,” a spokesperson said.

If not identified by that deadline, TxDOT will move forward with its expansion proposal, sans caps. While the city is required to identify the main project funds by fall 2024, TxDOT officials said the city could raise funds for amenities that will go on top of the deck plazas after that deadline.

“The city could spend the duration of construction to raise additional funds for amenities on top of the deck plaza, which will be constructed through their own contract once TxDOT construction if complete,” the spokesperson added.

On Tuesday, Mayor Kirk Watson joined Morteza Farajian, executive director of the U.S. Department of Transportation’s Build America Bureau, in signing an Emerging Projects Agreement. This agreement will help the city identify federal funding opportunities for several mobility projects, including programs like Project Connect and Our Future 35 Cap and Stitch.

Mike Trimble, director of the city’s Corridor Program Office, told KXAN Tuesday this collaboration will help the city as it prepares to identify those Cap and Stitch funding sources before the fall 2024 deadline.

“What we’re trying to do is see how we can minimize the impact on taxpayers by looking at other funding options, seeing what other things might work,” he said.

Right now, Trimble said his office plans to analyze different funding opportunities over the coming months before bringing several funding scenario recommendations to Austin City Council this summer or in the early fall.

As for elements of the project, the most common comparison officials have cited is the Klyde Warren Park up in Dallas. That features parkland and community recreation space above a sunken highway.

Here in Austin, Trimble said his office has done initial community engagement elements, adding early responses have shown residents want to find ways to incorporate and acknowledge I-35’s historic legacy of segregation into the project.

“There are ways to address some of the impact [I-35] has had on the communities over time, as the highway was put into place in the mid-20th century,” he said. “So that’s definitely a priority we heard from the community.”

Other early feedback noted an appetite for features like gathering spaces, recreation and parkland. Trimble said his office is working on collecting more feedback in the coming months from community members to see which components take top priority.

Beyond that, Trimble said Our Future 35 is in the preliminary engineering and design phases, adding community feedback will help steer those designs as they progress.

“That’s really what we want to get out to the community and talk about,” he said. “As we start to look at those concepts for what goes on the caps, where they go, what they might look like. What do folks want to see? What do they care about?”