What to expect now that the construction has started
Carrie Moritz, Gazette
Garretson-to-Sioux Falls or Brandon commuters will have some major road construction to deal with over the next two years. On Thursday, March 28, the Exit 406 reconstruction project officially began in earnest, though preliminary work has been happening since last summer.
Interstate 90’s Exit 406, known to locals as the Brandon exit, heads north to Garretson via Highway 11. In a $41.3 million dollar project, the interchange will be converted to a Diverging Diamond style over the next two years.
For Garretson-to-Sioux Falls commuters, completion of the project will mean even easier interstate access. The road immediately to the north of the ramp will be widened to include a turning lane, and a longer acceleration lane will give drivers the ability to get up to speed prior to merging onto the interstate.
While the project will impact traffic in the short term, in the long-term, “it will help traffic flow,” said Area Engineer Harry Johnston of the SDDOT.
On Wednesday, March 27, project managers, engineers, designers, and more were on hand at the Brandon Golf Course to answer questions and explain maps at an open house information meeting. They were able to explain how the project would proceed both in 2024 and 2025.
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The first step on March 28 was to set up construction corridors. Then, on Monday, April 1, the main contractor, T&R Construction, planned to move all traffic into the southern two lanes of I-90 and begin work on a temporary off-ramp for the westbound exit. Once that is completed, they will begin both the widening of I-90 westbound to accommodate the longer acceleration lane and widening the bridge over the interstate. At the same time, Xcel Energy will be relocating power lines along I-90.
“There will be a lot of moving parts at once,” said a representative of T&R. T&R is the contractor for the I-229/Benson exit as well, and is locally-owned. The T&R representative noted that he lives in Brandon and understood personally what impacts the construction will cause.
Getting through the next two years will likely be a bit hairy, as construction corridors will be erected, traffic will be diverted to other lanes, and cars will drive next to large equipment on one of the busiest thoroughfares in eastern Minnehaha County. At no time, though, should the exit be completely closed.
“We will be keeping lanes open to traffic at all times throughout the project,” Johnston said.
Traffic on the interstate will be head-to-head until this winter and again next summer, eliminating two lanes during the busiest months of the year. All travelers should expect to see some delays.
And at times in 2025, the eastbound and westbound ramps will be closed, though they’re hoping it won’t be for long.
The project will be completed in two phases, the first in 2024 and the second in 2025. This year includes widening the westbound lanes and the northern bridge over the railroad on I-90, along with construction of the eastern side of the diverging diamond. In 2025, work will begin on the eastbound ramps, the southern bridge over the railroad on I-90, the western side of the bridge over I-90, and Highway 11 from the farm approach just south of CHS down to Redwood Boulevard in Brandon.
Highway 11 construction will include the installation of a median, widening of the road north of the interchange, and of course, widening the bridge over I-90.
Stoplights are not currently planned for the interchange during the project, unless it is discovered that temporary ones are needed for traffic flow issues, according to Johnston. Permanent lights will be installed during construction, and will be turned on as the project approaches the finish line.
The Diverging Diamond is a newer traffic flow option, which is being installed at 41st/I-29 and Benson/I-229 in Sioux Falls as well. Rapid City has one at I-90/Lacrosse, and Fargo/Moorhead has one along I-94. According to the South Dakota Department of Transportation (SDDOT), the Diverging Diamond reduces the chances of collision by nearly half, and accommodates more traffic than traditional interchanges. The accommodation of more traffic has been sorely needed as Brandon exploded in size over the past two decades, with Exit 406 becoming a major traffic point.
“There will be a learning curve,” Johnston pointed out, not just while the project is ongoing but once the diverging diamond is completed. “Something we discovered [that helps] in Rapid City is the installation of recessed symbols on the roadway that show folks if they’re in the correct lane. So if they see the symbol for I-90 in that lane, they know that’s the one to get onto the interstate.”
For his part, Johnston is excited to see the project come to this point. It’s been a long process in the planning and development stages, which has been around 8-10 years from conception to construction. He lives in Brandon, and knows how difficult traffic has been as the area has grown.
Other attendees seemed excited, if a bit apprehensive.
“It’s hard to be mad when our small town can get something like this,” said one open house attendee. She acknowledged that she knew Brandon had grown to over 11,000 people, but she still considered it to be a small town.
Many were questioning how businesses along Highway 11 would be impacted.
“I work for the quarry just north of Corson,” another attendee remarked. “We see this exit about 8 or 9 times a day, so we’ll be following the changes closely.”
The engineers and representatives answering questions did their best to put business owners at ease, explaining how they would attempt to ensure commuters and traffic to businesses would not be too heavily impacted during construction.
For Garretson-area drivers who are headed to Brandon along Highway 11, while some congestion is to be expected, Johnston doesn’t expect it to be much worse than it has been over the past several years.
That said, drivers do have options. From Garretson, westbound travelers who wish to completely avoid the construction can turn west on 258th Street (also known as the "Renner road") and access Sioux Falls via 478th Avenue/Veteran’s Parkway (the Eros road) or 476th Avenue/I-229. Eastbound travelers can use 486th Avenue, and to access Brandon itself without encountering the construction, travelers can use 484th Avenue (the "Beaver Valley road").
Project information can be found at https://dot.sd.gov/I90-Brandon. For text updates, text “I90Exit406” to 605-566-4041.
