SIOUX FALLS, S.D. (KELO) — While he lives in Pierre, Steve Gramm knows Sioux Falls’ roads really well. 

For more than 30 years, Gramm has been working for the South Dakota Department of Transportation. His current role is a planning squad leader and he’s tasked with studying and planning for many of the city’s interstate interchanges. He’s helped produce the 2010 and 2020 decennial interstate corridor reports.    

“We pretty much studied the interior loop of Sioux Falls and we’ve reconstructed a lot of those interchanges,” Gramm told KELOLAND News on Monday. “We’re starting now to get out and spread out on the periphery.” 

One of those projects on the outskirts of Sioux Falls is Interstate 29 Exit 86 for Renner and Crooks just north of I-29’s interchange with Interstate 90. Gramm will be hosting a public meeting open house at 5:30 p.m. to 7 p.m. Wednesday at Jefferson High School to discuss early ideas for changes to the interchange. 

Gramm said he looks to hear from people who drive at that interchange nearly every day. He said DOT traffic numbers are based on one day’s worth of traffic collection and DOT doesn’t get information about “close calls for crashes.” 

“What are those problems that they see driving it every day,” Gramm said. “It might not occur every day, but it occurs often enough that they notice.” 

The Renner/Crooks Exit 86 study is one of the latest in a long list of interstate interchange studies Gramm and the DOT has worked on in the past few decades. In Sioux Falls, the DOT has studied more than 15 different interstate interchanges including I-29, I-90 and I-229. 

Map of Exit 86 from the SD DOT project website.

Gramm said the DOT aims to maintain a grade level of C or better when it comes to interstate interchanges in urban areas. 

“It’s a calculation of traffic volumes and how many are turning from each direction,” Gramm said. “How long is the delay? Are you waiting at the stoplight? It’s assigned a letter grade, similar to school.” 

Gramm said the decennial studies help forecast when interchanges might reach D grades or lower and that notifies the planning time to start looking at the interchange in more detail. 

Possible park and ride facility

Located north of Sioux Falls, upgrades to Exit 86 for Renner and Crooks could include the possibility of a park and ride facility. On the project’s website, there’s a park and ride facility survey where people would park and then carpool into Sioux Falls to reduce traffic and vehicle use. 

Gramm said the county sheriff’s office has been called on more than a few occasions to move people from using private parking lots for a park-and-ride situation. 

“We’re trying to gauge if there is really a public need for that type of facility at that location,” Gramm said. “That’s something we’ve never done before with any of these interchange studies. Would it be a benefit to have a parking lot there so people can meet and grab a carpool so only one vehicle has to go into Sioux Falls rather than 10.” 

SDDOT Park and Ride facility survey.

Gramm said there is a park and ride location alongside Interstate 90 at Exit 17 for Deadwood. On the north side of that interchange there’s a parking lot that Gramm called a meeting spot for people to combine. 

He said park and ride spots are more popular in the Twin Cities and Chicago where the parking location ties into more public transportation from a bus or a train. 

“We’re trying to gauge if there is a desire for such a facility,” Gramm said.

Gramm said if people can’t make Wednesday’s meeting all the information presented will be made on the project website and there will be a two-week public comment period.     

Limits with the standard diamond interchange 

Like many interstate interchanges, the I-29 Exit 86 for Renner and Crooks is currently a diamond interchange. According to the 2020 DOT report, there’s 153 interstate interchanges in South Dakota and 77 were identified for improvements.

Gramm said the standard diamond interchanges can be limited when there’s a higher number of people looking to make left turns. 

“You can always add lanes but the more lanes you get there, the more lanes left turns have to cross,” Gramm said. “If they just wanted to go through the crossroad all the time and never want to get on the interstate it would work perfectly fine. But then we wouldn’t have an interchange, there would just be a bridge over the interstate.” 

Over the years, Gramm said DOT officials have learned certain designs work well up to a certain traffic level and then they break down. He said as different ideas get implemented across the country and analyzed that helps feed into programs that determine the grade level of service.