About the Project

Corridor Overview

I-39/90/94 is part of Wisconsin’s “backbone system," a network of multi-lane highways connecting all major population and economic regions of the state. The I-39/90/94 Corridor is of vital importance to the region, the state and the nation and is relied on for its freight mobility, tourism and employment access.

The project corridor is 67 miles long and includes the longest stretch of three concurrent Interstates (29 miles) in the country.

67
MILES
113
BRIDGES
4
COUNTIES

Proposed Improvements

The I-39/90/94 Corridor Project will add a general-purpose lane in each direction along the present freeway alignment throughout a majority of the project corridor. I-39 from where it splits from I-90/94 to Levee Road will be reconstructed with the same number of lanes as the existing freeway.

Collector-distributor lanes will be added from WIS 30 to US 151 between the I-94/WIS 30 and US 151/High Crossing Boulevard Interchanges.

Auxiliary lanes will be added between the US 12/18 and I-94/WIS 30 Interchanges and at certain locations between the US 151 and WIS 19 Interchanges.

The project will also include improvements to 15 existing interchanges and the potential addition of two new interchanges. Use the interactive project map below to learn more about the interchange improvements.

15
existing
interchanges
2
potential new
interchanges
1
interchange
removed

Interactive Project Map

Corridor Updates

PDF of Project Corridor Map

Select a location ⬤ on the map below or a location name from the dropdown list ▼ to learn more about travel or construction updates happening along the project corridor.

Select a location name from the dropdown list ▼ to learn more about travel or construction updates happening along the project corridor.

US 12/WIS 16
WIS 13
WIS 23
US 12
WIS 33 (I-90/94)
WIS 33 (I-39)
Cascade Mountain Rd
I-39 I-90/94 Split
County CS
County V
WIS 19
US 51
Hoepker Rd
US 151
High Crossing Blvd
I-94/WIS 30
Milwaukee St
Map of the I-39/90/94 project corridor with location markers at each project interchange. The portion of the corridor between WIS 19 and US 12/18 shows the planned auxiliary lanes and collector-distributor roads.
Selected Location
Select A Location
High Crossing Boulevard will remain a half diamond interchange, but the ramps to/from the south will have improved separation to address congestion and safety concerns.
The WIS 13 interchange will be reconstructed in a similar footprint as the existing trumpet interchange with ramp design improvements to allow for speeds closer to Interstate speeds when entering or exiting the freeway. Longer acceleration and deceleration lanes are also included.
The WIS 23 interchange will be reconstructed in a similar footprint as the existing diamond interchange. New ramp alignments will improve sight distances.
The US 12 interchange will be reconstructed as a diverging diamond interchange (DDI). The reconstructed ramps will allow vehicles to enter or exit the Interstate at speeds closer to the posted speed.
The WIS 33 interchange at I-39 will be reconstructed as a diamond interchange. The elevation of this interchange will be raised to avoid flooding. The ramp lengths will also be increased. Roundabouts will be added to the ramp terminals to improve traffic operations and safety.
The I-94/WIS 30 interchange is a four-legged system interchange where I-39/90 meets I-94 to the east of the interchange and WIS 30 to the west. All left-hand entrance and exit ramps will be removed, which helps reduce weave movements compared to the existing interchange configuration. Ramp speeds will be closer to freeway speeds than they are today.
The existing US 151 interchange will be reconstructed so that the freeway-to-freeway movements to/from the east are free-flow movements. East Washington Avenue will feature a diamond interchange to provide local access and slow traffic coming from the freeway. The US 151 interchange at Nelson Road/American Parkway will be moved slightly northeast to Eastpark Boulevard to provide appropriate weave distances between the Interstate and the interchange.
Potential New Interchange
‍
Hoepker Road is an overpass on I-39/90/94. The city of Madison requested WisDOT evaluate an interchange at Hoepker Road, which would provide access to ongoing business and residential development, including the American Family campus and UW Health hospital. A shifted diamond interchange could be constructed depending upon a funding agreement with the city of Madison. The freeway would be shifted to the east to allow enough room for the southbound ramps on the west side of the freeway.
The US 51 interchange will be reconstructed as a partial cloverleaf interchange, which is a similar footprint as the existing interchange. Access to US 51 at North American Lane and Daentl Road will be closed to improve traffic operations. The entrance and exit ramps will be lengthened. Extended entrance ramps will allow more time to merge.
The County V bridge over the Interstate was reconstructed in 2002. A large development is proposed along County V just west of the interchange that would generate increased traffic demand. The developer is coordinating with WisDOT, Dane County, the village of DeForest, and FHWA to complete a separate environmental review that analyzes the impacts of any proposed improvements at the interchange.
The County CS interchange will be reconstructed as a diamond interchange with roundabouts. The ramp lengths will be increased to better allow for speeds at or near Interstate speeds at the ramp merge points.
The Cascade Mountain Road interchange will be removed to improve safety. Access to Cascade Mountain Road will be provided through a roundabout on WIS 78, which will be part of the I-39 and I-90/94 split interchange reconstruction.
The WIS 33 interchange at I-90/94 will be reconstructed as a partial cloverleaf interchange with a similar footprint as what exists today. Ramp curves will be realigned to improve line of sight and driver comfort entering and exiting the Interstate. Acceleration and deceleration lanes will be lengthened. Roundabouts will be added to the ramp terminals to improve traffic operations and safety.
Any improvements to I-39/90 in the interchange area will be limited to freeway improvements necessary to transition to the eventual selected freeway alternative north of the interchange.
The reconstructed WIS 19 interchange will feature a u-ramp. The u-ramp will consolidate intersections along WIS 19 and alter the ramp locations to avoid railroad conflict. This will increase capacity along WIS 19 from four lanes to six lanes from Pepsi Way to Tierney Crossing.
Potential New Interchange
‍
Milwaukee Street dead-ends near East Hill Parkway and does not cross I-94. The city of Madison requested WisDOT evaluate a potential interchange in this location. A partial cloverleaf interchange could be constructed depending upon a funding agreement with the city of Madison. The potential new interchange would provide needed access for area residents who currently have a long trip to reach an Interstate interchange.
The US 12/WIS 16 interchange will be reconstructed in a similar footprint as the existing diamond interchange. The improved ramp design will provide better line of sight. The 60th Street intersection will also be realigned to provide better line of sight. Roundabouts will be included at the ramp terminals to better manage traffic safety.
The system interchange will be reconfigured as a three-level interchange. All system-to-system movements will be right-hand ramps. An embedded diamond service interchange will provide access to WIS 78, which will also provide access to Cascade Mountain Road.
Auxiliary Lane
An auxiliary lane is an extra lane between ramps that makes it easier to merge or exit without slowing down highway traffic.
Collector-Distributor (C-D) Road
A collector-distributor (C-D) road runs parallel to the main travel lanes of a highway to handle merging and exiting traffic, keeping the main lanes moving smoothly.

Purpose and Need Summary

The purpose of the I-39/90/94 Corridor Project is to address existing and future traffic demands, safety issues, aging and outdated infrastructure, and corridor resiliency.

The need for the transportation improvements in the I-39/90/94 corridor is demonstrated through a combination of factors including the following elements:

Traffic Demands
Safety
Needs
Bridge Conditions
Pavement Condition
Corridor 
Resiliency
Full Purpose and Need Document →
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Traffic Demands

Roadways are typically designed to accommodate traffic volumes projected to occur 20 years in the future. Level of Service (LOS) is the measure of a roadway’s congestion. Sections of I-39/90/94 will operate at unacceptable Levels of Service by 2034, and most of the corridor will operate unacceptably by 2050 in the absence of improvements.

Safety Needs

The I-39/90/94 South Section (between US 12/18 and WIS 60) crash rates exceeded the statewide average crash rate at interchanges. The North Section (between WIS 60 and US 12/ WIS 16, and I-39 from the I-39 I-90/94 Split to Levee Road) has crash rates along portions of the mainline at or higher than the statewide average. Crash rates at two of the interchanges (WIS 13 and US 12) are twice the statewide average.

Bridge Conditions

Within the I-39/90/94 corridor, there are 113 bridges, of which 84 will be over 50 years old in the year 2030. Further, many bridges do not meet current standards for bridge height or width clearances.

Pavement Condition

Pavement maintenance projects in the I-39/90/94 corridor are anticipated in 24 of the next 30 years somewhere in the corridor, which presents ongoing travel delay and congestion for daily commercial and recreational traffic. Eventually, full pavement replacement is more cost effective than more repair.

Corridor Resiliency

Flood events causing partial or full Interstate closures since 2008 have impacted vital connections for commerce and emergency services. Both I-39 and I-90/94 are in a low area as they cross the Baraboo and Wisconsin Rivers. The Baraboo River flooding is problematic because it affects both I-90/94 and I-39, which has substantial impacts to both state and national commerce.

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