Alternative to MoPac “double-deck” being studied

In the wake of public outcry against a proposal to add elevated lanes to MoPac Expressway over Lady Bird Lake and Zilker Park, the Central Texas Regional Mobility Authority is considering an alternative that the Austin Transportation Department first put forward in May.

The staff alternative cuts out a “double-deck” design and a southbound flyover connection with Cesar Chavez Street that raised eyebrows after the Mobility Authority presented the elements as part of its preferred proposal to the public back in February.

Mobility Authority Executive Director Mike Heiligenstein told the City Council Mobility Committee on Wednesday that his organization will take additional public feedback and is now considering both options, among others, as part of its MoPac South expansion project.

“Given the input that we received in the community and from entities such as yourselves, we decided to step back a bit and look at extending the program, extending the comment period, extending the time that we got input from both the city and other entities that had a stake in the process,” Heiligenstein said.

Council Member Ann Kitchen, who chairs the committee, provided her own perspective on the public response.

“I think that what came to our attention and what was causing much of the angst about the proposal was, or is, the ‘double-decker’ aspect. I’ll use that term because that’s what’s most recognized by the public,” Kitchen said. “I appreciate the opportunity for the city to work with the RMA to come up with an alternative to that.”

The Mobility Authority, Heiligenstein explained, has met with city staff three times – most recently on July 31 – to discuss the alternative proposal and is developing its final schematic and analyses to present to the public for comment at an open house and a “virtual” open house that will most likely take place in early fall.

The virtual open house will be a website featuring the same information that will be available at the open house.

Heiligenstein added that a set of stakeholder meetings will begin in late August, and a University of Texas Center for Transportation Research study of MoPac South’s potential impacts on congestion downtown is nearing completion.

MoPac South, which is part of the Capital Area Metropolitan Planning Organization’s 2040 Regional Transportation Plan, includes adding to MoPac as many as two tolled express lanes in each direction between Cesar Chavez and Slaughter Lane, with the goal of relieving congestion.

“The city’s concept is one of the primary ones that we are looking at, but there are five or six others,” Heiligenstein explained. “Some of those involved one lane in each direction; they involved no direct connection downtown and so forth. So there’s a number of concepts that we are reviewing at this point.”

All of these proposals, Heiligenstein said, will be available for scrutiny and feedback as part of the public input process.

Transportation Department Director Robert Spillar said that the staff alternative would add two express lanes in each direction to MoPac. Aside from eliminating some controversial elements from the previous proposal, it still includes some tentative details.

“One thing that I wanted to stress here is that these were not engineered concepts when they were given to CTRMA, and so we fully expect a back-and-forth discussion, as is happening now, to make sure that they’re physically doable within the corridor,” Spillar said.

The staff alternative replaces the southbound Cesar Chavez flyover with a loop ramp from Lake Austin Boulevard and introduces separated collector-distributor lanes to MoPac to discourage cars from weaving between lanes.

The Texas Department of Transportation defines a collector-distributor as “a type of road that parallels and connects the main travel lanes of a highway and frontage roads or entrance ramps.”

“We’re asking to, in a sense, segregate the movements,” Spillar said. “So, we know that there’s a number of movements from north of the river to just south of the river – specifically the (RM) 2244, Bee Cave (Road) corridor. Can you segregate those off from some of the other movements?”

The staff alternative, Spillar acknowledged, still has the potential to impact Zilker Park in its own way. “Any intrusion to the park would be at about 50-plus feet above your head over what is now a parking lot and/or a maintenance area of the park,” he explained. “I still think that’s a hurdle to overcome, but it’s one that I think the community should have a discussion about.”

Spillar added that there are still other elements to be vetted and other questions to be answered as the process moves forward. “We continue to work with the Regional Mobility Authority,” he said. “I would envision it’s highly likely that a hybrid alternative might come out at the end, hopefully incorporating many or all of the city ideas or other ideas, as they’ve said they’re looking at other options from other folks.”

Concept rendering for Austin Transportation Department MoPac South alternative courtesy of the Austin Transportation Department.