New Diverging Diamond Interchange to open at I-43 and Brown Deer Road

Brown Deer Road DDI. Photo courtesy of WisDOT.

The Wisconsin Department of Transportation (WisDOT) is notifying the public of a significant milestone associated with the I-43 North-South Project. On Saturday morning, November 23, WisDOT is scheduled to open southeastern Wisconsin’s first Diverging Diamond Interchange (DDI) located at I-43 and Brown Deer Road in Milwaukee County.

A DDI is a type of highway interchange that improves safety and traffic flow by making it easier for drivers to turn left. DDI’s briefly shift traffic on the local highway to the opposite side of the road allowing free flow, left turns onto the interstate.

Benefits of a Diverging Diamond Interchange

The Brown Deer Road interchange has a significant amount of current and projected traffic volumes making left turns onto the interstate. With the new DDI briefly shifting traffic to the opposite side of the roadway, free flow left turns can occur without having to cross oncoming traffic or needing to stop. This type of engineering reduces the number of ways vehicles can collide by almost 50% and eliminates the most severe types of crashes. Other benefits include less congestion, a smaller footprint than the previous cloverleaf interchange, improved merging onto and off the freeway, and protected bicycle and pedestrian pathways.

Brown Deer Road DDI. Graphic courtesy of WisDOT.

Driving Through Diverging Diamond Interchanges

• Following the signage, signals and pavement markings, motorists go through the first set of traffic signals and then cross over to the left side of the roadway. Traffic appears as if on a one-way street.
• By being on the left side of the roadway, all left turns onto the interstate are now free flow, meaning vehicles do not stop to access the ramp.
• Vehicles going straight simply proceed through a second set of traffic signals and cross back to the right side of the road.
• Drivers looking to make a right turn onto the interstate will approach the interchange as they normally would.
• Bicycles and pedestrians safely cross traffic to a center pathway protected by concrete barriers.
• Watch WisDOT’s animation video here: https://www.youtube.com/watch?v=kRLS6miH9oY

Project Update

The DDI is scheduled to open on Saturday, November 23. This work is weather dependent and subject to change. After opening the DDI, crews will continue to work on finishing the remaining portions of the interchange. Drivers can expect intermittent, off-peak hour lane closures in the areas where work is taking place. All ramps will remain open.

The entire I-43 North-South project is scheduled for completion in mid-2025. Learn more about the project here: https://projects.511wi.gov/43north-south/

NOTE: This press release was submitted to Urban Milwaukee and was not written by an Urban Milwaukee writer. While it is believed to be reliable, Urban Milwaukee does not guarantee its accuracy or completeness.

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