‘Diverging diamond’ interchange on I-94 near stadium would lower project costs

Listen to this article

Plans to turn State Highway 175’s intersection with Interstate 94 near American Family Field into a diverging-diamond interchange could result in a project that’s both smaller and less costly.

That’s what representatives of the Wisconsin Department of Transportation told local officials in a briefing this week. WisDOT is looking at rebuilding the so-called Stadium Interchange as part of its plans to overhaul a 3.5-mile stretch of I-94 between Milwaukee’s Zoo and Marquette interchanges. WisDOT had originally proposed rebuilding State Highway 175’s interchange with I-94 with a structure that would be even bigger than the current interchange.

But following recent traffic studies, WisDOT officials decided to further study proposals to rebuild the interchange as a diverging diamond. Diverging-diamond interchanges, in use already in several places in Wisconsin, are often considered safer than other sorts of intersections because they prevent cars that are turning left from having to cross in front of oncoming traffic. They do this by causing vehicles to move temporarily to the left of traffic coming in the opposite direction before switching back to the normal position.

WisDOT officials estimate the change would reduce the project costs by between $70 million and $90 million. The diverging-diamond alternative also would stand 25 feet less high than the structure originally proposed.

But there would be drawbacks. For one, I-94 would have a lower speed limit as it approaches and goes through the State Highway 175 interchange.

The state is meanwhile still studying if should simply rebuild the current six lanes of I-94 running between the Zoo and Marquette interchanges, or if it should add two more lanes. WisDOT officials maintain that a wider highway will be safer for commuters who rely on that stretch of highway nearly every day. But community activists have worried that a wider interstate will merely give white suburbanites an easier means of getting to and from the city while leaving Black neighborhoods even more isolated than they are now. Construction on the I-94 overhaul is scheduled to begin in 2025 at the earliest.

The state is holding two public meetings next week on its plans for rebuilding Interstate 94. They will take place on:

• Tuesday from 4 p.m. to 7 p.m. at the Tommy Thompson Youth Center at State Fair Park, 640 S. 84th St.; and
• Wednesday from 4 p.m. to 7 p.m. at Marquette University High School, 3401 W. Wisconsin Ave.