You can see the light at the end of the Kilbourn Tunnels – but only if you can get inside first. And that’s not possible when the Downtown freeway ramps under MacArthur Square are closed.
Over the past 35 years, the two tunnels have been subject to eight extended closures, with the longest one stretching over more than two years of Marquette Interchange reconstruction in the early 2000s.
The north tunnel, an on-ramp to northbound I-43, was closed for more than a year and a half. The south tunnel closed first for nine months, then again for four days, as it transitioned from a northbound I-43 exit to an eastbound I-94 off-ramp.
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Most recently, each tunnel shut down for about two months for lighting system upgrades earlier this year. According to Wisconsin Department of Transportation and Milwaukee Department of Public Works records and newspaper accounts, the other extended closures were:
- Two months in 1991, when the south tunnel closed for rehabilitation of the MacArthur Square parking garage.
- Six weeks in 1992, for repaving and other repairs to the south tunnel.
- Three days in 2010, for repairs to both tunnels.
- Six months in 2019, for garage-related rehabilitation lasting two months for the north tunnel and four months for the south tunnel.
- One week in 2020, for security-related traffic control during the mostly virtual Democratic National Convention.
- Four days in 2024, for the Republican National Convention.
Also, from 2014 to this spring, the tunnels closed for one day or less on 28 occasions for maintenance or as part of larger freeway construction projects, not counting five lane or shoulder closures for pavement marking, sign inspections and lighting work, WisDOT says. All told, one or both tunnels have been closed on one of every 13 days in the last 11 years.
While reasons for closures vary, the Kilbourn Tunnels have more unique complications than other freeway ramps, says Scott Reay, WisDOT regional bridge and tunnel inspection manager.
As tunnels, they have ventilation and lighting systems to maintain and inspect. They are also the longest of the five Milwaukee-area roadway structures officially recognized as tunnels, at 1,401 feet for the south tunnel and 1,299 feet for the north tunnel.
By comparison, the county-owned tunnels under the Mitchell International Airport runways extend 801 feet on South Howell Avenue and 640 feet on East College Avenue. The 381-foot city tunnel that carries North Ninth Street under MacArthur Square is the only one without a ventilation system.
And those things that look like tunnels in the Mitchell and Zoo Interchanges and on the Lake Parkway are considered “buried bridges” by federal standards, WisDOT spokesman Chris Verhyen says.
As part of MacArthur Square, the Kilbourn Tunnels are plagued by the same water leaks as the city parking garage. That was the driving factor behind the 1992 and 2019 closures. In the 2019 project, workers replaced water-damaged expansion joints holding up the tunnels beneath the Milwaukee Public Museum’s now-closed Pioneer Village exhibit, Reay says.
The tunnels also are unique in their joint ownership, which requires extensive coordination on every project. The city owns roughly the eastern two-thirds of each tunnel, plus the entire ventilation system, while the state owns the western one-third or so, plus the entire lighting system, city public works spokeswoman Tiffany Shepherd says. The city portions are part of the garage, while the state sections are underground, with the dividing line under Clas Park, the green space south of the Milwaukee County Courthouse, Reay and Shepherd say.
Most of all, the tunnels are just getting old. Like the garage, they date to the late 1960s, and rehabilitation “for a structure of this age is to be expected,” Reay says.
