The Interstate 39/90/94 67-mile corridor from near Madison to the Wisconsin Dells area is under review for a potential major project in a few years, and alternatives for each interchange are now available for feedback.
During public involvement meetings at Yahara Elementary School in DeForest Wednesday and Wisconsin Dells Middle School Thursday, the Wisconsin Department of Transportation presented up to four layouts for each interchange from its intersection with the Beltline Highway in Madison to just north of the interchange with Highway 12/Highway 16 in Juneau County near the Dells.
“We’re really trying to develop long-term solutions to the needs of the existing interstate,” said Daniel Schave, the department’s Major Studies supervisor leading the study. “We’ve developed alternatives for the interchanges along the corridor, including two potential new interchanges in the Madison area.”
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The two potential future highway exits will be on Interstate 94 at Milwaukee Street and at Hoepker Road off of I-39/90/94 just north of the major interchange with Highway 151. Increased population and employees in the area of those two intersections creates the potential for the additional interchanges.
Schave said that the department is looking at three alternatives for the mainline interstate itself. A potential managed lane (an additional left lane open and closed to traffic based on time intervals and traffic flow which is used as extra shoulder space when closed) from Madison to near Portage where I-90/94 splits from I-39 is a possibility. Another option includes adding a regular traffic lane along the entire corridor. Pavement and bridge replacement is being explored as well.
A small portion of I-39 extending from the split to just north of its intersection with Wisconsin Highway 33 is also being studied because of flooding concerns with the current area layout, according to Schave.
At four of the 17 studied interchanges, one of the alternatives is a newer concept. The diverging diamond interchange (DDI), which Schave said exists at roughly five major highway intersections statewide and has received positive feedback, creates traffic flow to the left side underneath the main highway to eliminate left-turns onto entrance ramps.
DDIs are being explored at I-39/90/94’s interchanges with Highway 51 and Highway V in Dane County, as well as I-90/94’s interchanges with Highway 12 and Highway 23 in Lake Delton.
“We’re very early in our study, so that’s why we have quite a large number of alternatives right now,” said Schave. “Over the next six months, we’re going to be narrowing down our alternatives.”
Factors in narrowing down alternatives will be traffic congestion and safety, according to Schave. WisDOT analysis shows that if no project is done along the corridor, the existing highway will need 24 maintenance and rehabilitation projects on pavement and bridges over the next 30 years. Traffic flow at major intersections, particularly in the Madison and Dells areas and the intersections at and near the I-39 split, could drastically worsen as well, according to the data.
Information about interchange alternatives and future project or lack thereof impacts is on the WisDOT website.