BELOIT—Construction on the Interstate 39/90 expansion project is expected to wrap up by early December marking the end of one of the state’s most intensive interstate projects after years of construction.

The expansion of I-39/90 from Madison to the Wisconsin-Illinois state line and the redevelopment of the Interstate 43 interchange in Beloit first saw design work released in 2012, with varying ancillary projects between 2013 and 2015 when work began on the corridor. The entire project spans 45 miles, expanding I-39/90 from four lanes to six lanes, and expanding to eight lanes in the Janesville area. Eleven interchanges have been reconfigured between Beloit and Madison.

“Beloit is the capstone to wrapping everything up,” said Wisconsin Department of Transportation (WisDOT) Project Communications Manager Steve Theisen.

In 2016, the first diverging diamond interchange (DDI) opened at Wisconsin Highway 11 (Avalon Road) just south of Janesville. The new interchange is a concept implemented by the Wisconsin Department of Transportation (WisDOT) to improve safety at dangerous intersections.

Bridge replacements over I-39/90 took place in 2017, with 2018 seeing interstate construction starting between Beloit and Janesville and preliminary work starting on the interchange with I-43 and Wisconsin Highway 81 (Milwaukee Road).

Since then, interchange work at I-43 has continued alongside the interstate expansion to the Wisconsin-Illinois state line and Cranston Road. The Travel Wisconsin Welcome Center near Beloit also saw expanded truck parking in 2020.

Beloit drivers will see a new configuration to enter Beloit thanks to the addition of the DDI at Highway 81 (Milwaukee Road). Upon completion, I-43 traffic with a destination in Beloit must exit at County Highway X (Hart Road) and follow Highway 81 into Beloit.

Weather permitting, construction is expected to be complete by early December, according to Theisen.

Recent work at the I-39/90 and I-43 interchange at Beloit included the setting of the remaining girders for the flyover ramps, along with pouring of concrete to begin to set the new bridge structures at the interchange.

Theisen said he was hopeful traffic would be shifted onto their respective sides of the interstate at the interchange area.

The entire interstate project is aimed at improving safety and mobility of one of the Wisconsin’s busiest travel arteries, with Theisen highlighting the major redevelopment at the I-43 interchange in Beloit.

“Our two goals were addressing safety and mobility and those outdated clover designs did not allow motorists to get up to speed to merge or diverge on those clover leaf ramps,” Theisen said. “Free flow ramps are much safer and obviously there’s a disclaimer that the speed limit is for ideal conditions. Slow down on the interstate if weather conditions are poor.”

This year has marked the final year of construction, something that’s culminated in cooperation between municipalities, businesses and motorists.

“The work that we’ve done has a lot of success stories and we’re going to try and implement strategies we learned over the course of the project in other projects across the state,” Theisen said. “It’s an exciting time for reflection and to see what we’ve accomplished. This is an exciting time for us to show that these improvements for safety and mobility will stand for decades to come.”