TXEXplainer: The Proposal to Bury I-35 Underground

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When Highway I-35 opened in 1962, Austin had just 200,000 people. Today, there are 900,000 in the city proper, and 2 million in the greater metro area. Those numbers are expected to double within the next 25 years. If nothing changes, the 19-mile commute from the suburb of Round Rock to downtown will take 2.5 hours by 2035.

Longhorns are concerned about this—as evidenced by the outpouring of comments we received after a recent episode of The Hook discussed UT architecture professor Sinclair Black’s proposal to rebuild I-35 through downtown, burying the highway underground and replacing it with a walkable, tree-lined street. Below, we take a closer look at the plan and answer some of the most common questions.

What would this plan look like?

Called Reconnect Austin, the proposal would bury I-35 from Cesar Chavez through 12th Street in an underground tunnel. A wide, tree-lined boulevard would take its place. It would be reminiscent of East Avenue, the surface street that was I-35’s predecessor—and according to its advocates, it would eliminate the geographic, economic, and racial barrier between East and West Austin.

Has this been done elsewhere?

The idea isn’t as far-fetched as it might seem. Similar “cut and cap” projects have succeeded in other cities. One of the biggest success stories is nearby in Dallas, where Klyde Warren Park was built over an eight-lane freeway. Since it opened in 2012, the park has won national awards and revitalized the northern edge of the city’s downtown. It’s also been credited with increasing property values. Other successful highway removal projects have been completed in San Francisco, Boston, and Portland.

Would it help traffic?

That depends on whom you ask. “Our plan would reconnect Austin’s street grid, and street-level traffic behaves differently than highway traffic,” Black told the Alcalde in 2013. “Don’t like a street? You can turn onto another one. You have options. You’re not stuck in one place like you are on the highway.”

UT transportation engineering professor Randy Machemehl disagrees. “Those streets are already full,” he says. “It’s a cool idea, but where are those people going to go? We need to add capacity to the whole transportation system.” Machemehl advocates for better public transit and more telecommuting, carpooling, and flex hours instead.

If it wouldn’t fix our congestion problem, then why do it?

Reconnect Austin supporters argue that they’re playing the long game. By investing in a project that would make downtown less car-centric, they want to change the way people live and move around Austin. Black is a proponent of New Urbanism, a popular design philosophy that advocates for dense, walkable cities rather than suburban sprawl. “Our objective is not to cut 30 seconds off your trip from the suburbs,” he said in 2013. “We would rather have you spend 30 minutes drinking a coffee at a sidewalk cafe with friends walking by and your kids playing in the park.”

Heyden Walker, an urban planner with Reconnect Austin, says affordability is an important part of this discussion. After all, there’s not much sense in making downtown Austin more livable if only the rich can live there. “The land that right now is frontage road could be used for affordable housing,” she says. “If you’re a teacher and you can’t afford to live close to the center of Austin anymore, there could potentially be housing for you in this corridor. I think that’s a real opportunity.” 

Would adding more lanes help?

In 2008, the state spent $2.8 billion to expand the Katy Freeway in Houston to 26 lanes, making it the widest in the world. After the expansion opened, commute times went up by 55 percent. Now the Katy Freeway is known as one of the biggest failures in the history of transportation engineering. It turns out that adding more lanes on highways actually makes traffic worse, as counterintuitive as that may sound. It attracts more drivers, longer trips, and more suburban sprawl.

This phenomenon is called induced demand, and it’s so well-established that researchers call it “the fundamental law of road congestion.” Essentially, as long as you make it cheaper and easier for people to drive on the highway, more of them will do it, and traffic will get worse. Making it less convenient to take the highway—by making drivers pay a toll, for example—has the opposite effect.

How would we pay for all this?

Good question. Reconnect Austin advocates say that by eliminating frontage roads, the plan would open up 30 acres to developers and 40 new acres of land for UT. According to Black, this revenue would eventually cover the cost of the project, which conservative estimates have put around $600 million. Supporters of Reconnect Austin are hoping that the city will create what’s called a Tax Increment Reinvestment Zone, which would allow the city to borrow money for construction and pay it back later with tax revenue created by the new development. A similar structure has funded improvements to Waller Creek and the Seaholm District.

If this plan doesn’t move forward, what will?

The Texas Department of Transportation is already planning to add an optional toll lane in each direction on I-35 (similar to lanes already under construction on MoPac) by 2020—a move that the Reconnect Austin proposal incorporates. State Sen. Kirk Watson voiced support for the cut-and-cap plan in May, telling the Austin Business Journal, “Doing nothing with I-35 is simply not an option. It’s going to get a whole lot worse if we don’t get after it.”

Reconnect Austin advocates continue to talk to community groups, members of city government, and the state in hopes of selling their vision. They’re hoping that TxDOT will commission a study, similar to one that was just completed in Dallas, to learn more about the options. Meanwhile, Austinites are still sitting bumper to bumper on I-35.

Rendering by Reconnect Austin, courtesy Heyden Walker.