SIOUX FALLS, S.D. (KELO) — If it wasn’t for developers the planned interchange at 85th Street and Interstate 29 would not happen.

The city of Sioux Falls and the South Dakota Department of Transportation were looking at a possible overpass for 85th Street at I-29 several years ago, said Shannon Ausen, an engineer with the city of Sioux Falls.

The city had believed an interchange at 85th Street and I-29 would be needed in the future, Ausen said, but several factors pushed the overpass plan.

“We knew we needed an interchange in (maybe) 20 years,” Ausen said.

While an overpass was being considered a group of developers advocated for an interchange, Ausen and Steve Gramm, a project leader for SDDOT, said.

The developers agreed to pay for an environmental assessment (EA) the study that can be reviewed by the public tomorrow at an open house and online.

An EA is required for an interchange project.

“(EA) looks at what’s the proposed project and what are the environmental impacts of the project,” Gramm said.

The EA determines if there are any endangered species such as long-eared bats in the project area as well as evaluating the impact on wetlands and noise factor, Gramm said.

An EA can cost from around $300,000 to $1 million depending on the project, Ausen said.

The city didn’t have the EA cost in any upcoming budget so it agreed to have the private developers pay the contract for an EA, Ausen said.

The area in the environmental assessment review. DOT graphic.

The advocacy of the developers moved what SD DOT and the city of Sioux Falls believed to be a necessary project down the road.

Roughly 17 years ago, the state Department of Transportation was looking at a possible interchange on I-29 at 85th Street, Gramm said. Gramm said he first learned of it in 2005 but it was a 2008 study that firmly identified the project.

SD DOT did a corridor study in 2008 as to whether or not another service interchange on I-29 could be constructed, he said.

The study reviewed 57th Street, 69th Street and 85th Street, he said.

“From that corridor study, 85th Street rose to the top…” Gramm said. “By far, it was easiest and cheapest one.”

The interchange proposal hit a few bumps as a recession hit at 2010 and even federal highway officials advocated for an overpass.

“It absolutely has been a process,” Ausen said.

“This project’s unique just in how long it’s been planned,” Gramm said.

Why is an 85th Street exit needed on I-29?

Gramm said development is happening near 85th Street and I-29 in Sioux Falls and Tea.

“Tea has had a lot of growth and the growth is largely in the northern part of the city, up towards 85th, said the city’s engineer Ben Scholtz of HDR.

An additional access to I-29 will benefit Tea as it’s another way to reach the city as well as an access to Sioux Falls and neighboring areas, Scholtz said.

“The biggest benefit is we are expanding our transportation network,” Ausen said. The interchange gets the city ready for more development in areas near 85th Street, she said.

Gramm sees a benefit for commuters to and from Tea who use I-29.

The planned 85th interchange at I-29 will also benefit the east and west traffic in Sioux Falls.

Sioux Falls has limited east and west connections, such as 41st Street, Gramm said.

“I think that’s where you are going to see your biggest traffic impact, especially when it first opens up,” Gramm said of the proposed project.

85th Street boundary between Tea and Sioux Falls

85th Street is considered by Tea and Sioux Falls as the boundary between the two cities, Ausen and Scholtz said.

The arterial road is big part of future development and planning for both cities. They are working on a joint pavement project for 85th Street.

About a mile and half of 85th Street near Tea is gravel, Scholtz said.

The plan is to pave the street and it will remain a two-lane but the design of 85th Street could change in the future, the two engineers said.

“The Tea side of 85th will be two-lane road, similar to a county highway for now,” Scholtz said.

No exit at 57th Street

Ausen said she gets asked about a possible interchange on I-29 at 57th Street.

That suggested interchange “is not going to happen,” Ausen said.

Gramm said an interchange at 57th Street is not practical or feasible. The Good Samaritan office complex is at 57th and I-29, he said.

“It would have been great to know in the 1950s,” Ausen said of the traffic and development on 57th Street.

And an interchange at 69th is not practical either, said Gramm said. The 69th Street and Marion Road intersection is too close to the interstate and the interchange for I-229, Gramm said.

“85th (interchange) is our future,” Ausen said of access to I-29.

The public can attend tomorrow’s open house on the EA from 5:30 to 7 p.m. at the Sioux Falls Lutheran School, 6715 South Boe Lane, Sioux Falls. Information online is also available at

Hard copies of the EA are available at the SDDOT office in Sioux Falls at 5316 W. 60th St. or at the Sioux Falls City Center at 231 N. Dakota Ave. or at the city hall in Tea at 600 E. 1st St.