To raise or to sink—that is the question for the future of I-35 through downtown.

The Texas Department of Transportation, the city of Austin and the Capital Area Metropolitan Planning Organization are considering proposals to either elevate or depress the interstate through the city's core. The concepts would add an additional northbound and southbound lane and reduce the number of entrance and exit ramps through downtown.

"It doesn't get more challenging than the downtown section, but within the challenges are opportunities and responsibilities," said Terry McCoy, TxDOT's deputy district engineer for Austin.

The city and transportation groups, which are teaming together to tackle I-35 transportation fixes, held another round of open houses in June to gather public feedback on the proposals. The open houses featured updated I-35 design concepts, including a modified version of the depressed proposal that would place a cap over portions of the interstate, creating land for potential parks or development through the city's core.

The concept follows the cut-and-cap proposal from architect Sinclair Black that received support from multiple city leaders and civic groups. While Black's plan proposes creating mixed-use development along the sunken and capped freeway, McCoy and Rob Spillar, city of Austin Transportation Department director, said they think building anything high intensity such as mixed-use development atop a sunken I-35 would be a bad idea because the corridor serves as a main arterial during a disaster.

However, Spillar and McCoy said that the basic idea of sinking and capping the interstate, allowing for potential parkland and a hike/bike trail, has received overall positive feedback.

"It's a really cool concept. Everyone we have talked to is excited about it and proud of it," McCoy said. "The motivation of what we are trying to do behind I-35 is to create a community initiative, and [we] want to make sure we are taking care of and satisfying as many needs and wants as we can."

More details about the potential costs and construction times for the proposals will likely be released in August, McCoy said. The chosen proposals will then be put through the environmental coordination process, which examines everything from the proposal's environmental impact to an overall operational assessment. The study could take approximately three to four years to complete, McCoy said.

Following the study's completion, TxDOT will announce which proposal it recommends and design an implementation plan.

While there is not significant funding for an overarching overhaul of I-35 through downtown, Spillar said it is crucial to have a plan in place for when money becomes available. He said that funding could potentially come from multiple sources.

Elevating the interstate would likely be cheaper, though the public has been more supportive of the sinking proposal, McCoy said. Sinking I-35 would also allow for caps to be placed above the interstate in the future as funding becomes available, he said.

Regardless of the proposal, McCoy said the goal has been to involve the public at every step.

"We are not in the business of trying to shove anything down anyone's throats," McCoy said. "We don't want the I-35 program to carry that connotation. What we're all about is what can people get behind, and if we can find something that is technically feasible that works, that the community can support, that's the match we are looking for."