AUSTIN (KXAN) — When we told you about the proposed toll lanes on Interstate 35, many of you reached out to us and asked, ‘Why more tolls?’

Transportation advocate John Langmore, who has worked with Capital Metro and the Lone Star Rail, gives us an idea on how adding tolls lanes are a key to helping reduce delay.

The overall goal is to have the proposed toll lanes run in each direction of I-35 from Ranch to Market 1431 in Round Rock to State Highway 45 SE near Buda. “It’ll take a long time and it’ll be a major initiative to round up the funding for a project of that size,” says Langmore.

Getting $8 billion for the project is one step, he says, along with the price and construction headaches. There will also be benefits, like less backup on I-35 and connections in downtown Austin like never before.

“There’s no question that if the project is built as it’s currently described, it would have two benefits. The first being, it would absolutely improve traffic congestion along I-35. Primarily because you’d be adding four lanes of new capacity. The other big benefit, of course, is removing the barrier between east and west Austin.”

Though covering I-35 with park space would look good, why more toll lanes?

“If you just add two lanes of traffic without variable tolls, they will fill up instantly and you will feel no relief within a very short period of time,” says Langmore. “They won’t get built if there’s not additional financial support coming from those projects themselves, which equates to tolls.”

He continued, “The thing about transportation projects in the United States today without additional financial support — especially projects in a dense urban core, where they’re much more expensive to build — they won’t get built if there’s not additional financial support coming from those projects themselves, which equates to tolls.”

Langmore says the only way to ensure the managed toll lanes don’t become congested themselves is to let the toll rate fluctuate. “So that it ensures only enough people use [them], that there will always be free flowing traffic on it.”

The first two express lanes would be built each way through downtown from Oltorf Street to Martin Luther King, Jr. Blvd., then expanding the entire length of the project. The plan also calls to remove the upper decks from MLK to Airport Boulevard.

“It’s a struggle to accept the fact that you have to pay a market price for access to free flowing traffic, on the other hand it’s really the only viable option to achieve free flowing traffic,” says Langmore.

What other cities have done

Adding toll lanes is one aspect but another is the idea of lowering I-35 by building underground. One of the models for the I-35 project is the LBJ Texpress lanes project just built in Dallas. It runs between I-35E and US 75 using toll lanes sunken below. Above it is a cantilever system where the highway and frontage road meet the higher ground.

But parts of I-35 In Austin could be even bigger, like in an infamous Boston project that revamped the entire city, becoming the most expensive highway in U.S. history.

Though the city is nearly 2,000 miles from Austin, lesson learned in Boston’s “Big Dig” may hit closer to home than we think.

“The city of Boston was totally disrupted but it has been forever transformed,” said Dan McNichol.

McNichol was the spokesperson for the “Big Dig” for 7 years and wrote a book about all the ups and downs of the project through its more than 20 years.

“The people lived with a lot of traffic changes, a lot of disruption, a lot of mud, dust and it was never ending it seemed,” he said.

The project tore up Boston’s roads — moving loud, ugly highways underground. Construction costs climbed $11 billion over budget, spanning three decades and six presidents. At one point it even turned deadly when concrete slabs fell from a tunnel onto a woman driving below.

McNichol sees why Austin drivers may look at this and get concerned for what the city here is about to take on. But the payoff, he says, will be life changing.

“This is going to be what makes Austin, for the next no lie 50-100 years an even better city,” said McNichol.

McNichol says the changes in Boston opened up 1,000 acres of property for new development along the water through downtown and traffic flows much smoother. He has hope Austin’s project will move much faster but advises drivers to be patient with the process and not lose sight of the end goal.

“Enjoy the ride, it’s going to be bumpy and messy at times but it’s the kind of thing that brings attention to a great city.”

TxDOT wants to hear what you think about the proposed changes. Public input and open houses are scheduled to begin next spring. Officials say an environmental study of this entire project should be done in the winter of 2019. Then, construction on the toll lanes for downtown should begin in 2021.